Click code rework

Fixes #646, #579, #863

Completely redoes the click code.  Moves all click related code into code/_onclick for reference.  Also moves hud datum code and all the screen object code I could find into code/_onclick/hud, as it is related.  Item attack(), attackby(), afterattack(), and attack_self() have been moved into item_attack.dm for consistency.

Completely removes dummy objects and adds atom.Adjacent(user).  This proc checks for border items and anything marked with throwpass for determining whether or not you can reach a given square.  A turf helper, ClickCross(), was added to facilitate this.

Removes the monolithic Atom.Click() proc in favor of an overridable click handler attached to mobs.  Click code no longer uses the : path operator as a consequence, and mob/lastDblClick has been moved to Client/next_click.  A few end arounds were necessary (screen objects, buildmode, and spells), but this has been handled by repurposing Atom.Click(); if you have special click code, insert it in the object's Click() function and return 1 to prevent normal processing.

This update adds support for attack_ghost(); the previous "new" click handler had support for it but was never finished.  I have taken the liberty of letting ghosts click portals, the gateway, and the teleporter to jump to the intended target square, and kept the previous default action of examine()ing every damn thing you click.  It is to be suggested that you could do more with this proc when ghost interactions are enabled.

This update also adds support for double clicking.  It is currently only used for ghosts and AIs, because the original (first) click still registers normally.  For both of these, double clicking a square will jump you to it, and double clicking a mob will follow it.  In the case of ghosts, double clicking bots and the singularity will also set you following it; if you double click your own corpse, you will re-enter it; this also works if your body is in a closet, sleeper, DNA scanner, etc.  Default mobs ignore double clicks as normal.

-- NOTE --

There are two flags which were previously unused or misused by click code: USEDELAY and NODELAY.  Ostensibly, USEDELAY would double the normal 1sec delay, and NODELAY would remove it.

Using either of these flags as intended would significantly affect the timing of the game.  In particular, USEDELAY is currently applied to guns and about everything else that acts at range.  I am adding USEDELAY as a half-second increase for now, but I have not put a significant amount of thought into it.  I considered lowering the normal 1sec delay to .8sec to balance it, but the consequences of that on combat involve more calculations than I care to make.

NODELAY seems to never have been used, and I did not implement it, but I could do so trivially.
Adds click delay to item quick buttons.  Updates changelog.
Fixes NOBLUDGEON flag

Apparently bitflags only work for up to 32768; bitflag 4 SEEMS unused so I have commandeered it.

Also, it apperas the TABLEPASS flag (as distinct from passflags PASSTABLE) does absolutely nothing, but I am not going to remove it here.
Adds an alt-click to vents for mobs that can ventcrawl.

Reorganizes the ventcrawl code to be a little flatter.

Removes the attack_animal default from slime attacks.  Apparently some code had assumptions about animals and I don't want to get into what that all is yet.
Reverts a change made redundant by #1217

rebasing accidentally made two copies of the function in living.dm, removes the ones I added.
Timing adjustments

attack_self use should be somewhat more standard; previously the activate object verb (and pagedown) had no delay at all.

Lowers the time taken when interacting with things on your person or in your square.
Adds telekinesis to click code.  Fixes issue #1202, #1129, #247.

This adds two atom procs, attack_tk() and attack_self_tk().  attack_tk is used as per attack_hand; attack_self_tk exists on all atoms (not just items) but is similar to the item proc, but without the assumption that it is in the user's hand.

Removes the functionality where entering throw mode would create a tk grab, as it is redundant.

As a default, attack_tk does the following:
* Creates a telekinetic throw for items and un-anchored objects
* Does an attack_hand (paw, animal, etc) for anchored objects
* Does nothing to mobs

As a default, attack_self_tk does nothing.  An attack_self_tk was added to closets to open and close them since that's a common thing.

The following items have added attack_tk procs:
* Fire axe cabinet, extinguisher cabinet, and bedsheet bin will drop into their square instead of putting it in your hand
* Doors only open telekinetically if they require no access
* Chairs will rotate if nobody is buckled to them
* Filing cabinets will remove a paper at random.
* Tables and racks return to prevent telehulk smash

This is INCOMPLETE.  Adding proper TK interaction to everything is something best done in pieces.

In particular, interacting with mobs and items both open up the floodgates for bugs, so we/I need to decide how we want it to go before we commit, and then fix bugs along the way.  Stumbling forward, fixing bugs, and then changing course halfway would be a bad idea.
Bugfixen

Modifies Adjacent() for items, to allow items to be accessed properly inside each other and the user.  This fixes a few bugs seen in testing.
Sets a maximum telekinesis range (in case you were using cameras).

The telekinetic grab now does nothing at all in melee combat.  This prevents double messages where you attack them with the object telekinetically, and then also attack them with the telekinetic grab.

Crayons had a bug where they were drawing at all distances.  This is because in old click code, afterattack() only happened at range when you had the USE_DELAY flag, which is no longer true.  Proper behavior is to use parameter 3 (proximity_flag), which is 1 when adjacent or 0 if inaccessible.
Rebase past 6e83288a7837e42d35e451064ce20dde31acff37 to fix conflicts
Fixes #1164
Glove update

Integrates gloves into click code.  Gloves now have a proc/Touch(atom, proximity) which is called before humans do an attack_hand().  It can also occur when you click on something at range, so be sure to check the proximity flag.

Adds code to make ninja gloves work properly with this and pulls it out of the various attack_hand() procs.

Other suggested uses: secret society rings, magic/cult gloves, weaponized gloves (chemical, electric, needles, etc), powered exosuit hands (for picking up crates), I dunno, there are options
Bugfixen and minor changes.  Fixes #136.

Adjusts the click code to not use client/Click().  The code is largely unchanged, except that it allows the compiler default behaviour of calling atom/Click(), and then forwards the call to mob/ClickOn().  I had some reports that melee combat mixed with movement was behaving oddly, and I believe it may be due to the use of client/Click; the byond documentation says that redefining client/Click() causes additional overhead, and it isn't strictly necessary.

Alters the way double clicks are handled, in an attempt to better handle clickspam, as often occurs during pitched combat.  This may also be responsible for the above, but I don't know.

Inserts proximity (aka flag) checks in all afterattack() procs.  The old assumption was that unless an item used the USEDELAY flag, afterattack() was only called when adjacent, but this is no longer true.  This led to beakers, soap, crayons, etc, all being usable at all ranges.

Removes the NODELAY flag, which was unused.  Removes all existing uses of the USEDELAY flag so that it can be readded to things that need extra delay.

Removes the hand_* procs, previously used by restrained actions.  Instead, the mob helper mob/RestrainedClickOn() has abosrbed basically all the functionality they were used for, which is really only monkeys with jungle fever.

Adds a special case of the Adjacency() proc for doors.  This fixes #136, airlocks being unreachable due to border fire doors.  However, this only takes us back to the unpleasant position where you have to open-hand the door, switch to a crowbar, and pry open the firedoor; it still needs a better fix.
Additional comments, move some code

Should improve documentation of new and old click code
Merge pull request #1206 from SuperSayu/newclick

Click code rework