Strictiy terrain special enum
Fix inability to walk on swamps
Strictify special node type enum
Strictify special node context enum
Merge the XXX_BLOCK and SANCTIFY special nodes into a single, more versatile IS_CONTEXT node
Finish strictifying special node type enum (forgot the scenario editor)
Add a lot of stuff scraped from *i's version of the code, plus a couple of additional bits.

Adapted from *i:
- Show a confirm dialog when interrupting a special node sequence
- New monster special ability: call global special node (as an action, not on death)
- New item special ability: call global special node
- Check there's a monster death special before calling it (wasn't necessary before, might be now with the special queue changes)
- Queue specials that are triggered while another special is in progress, instead of ignoring them; they will be run after the current special in progress finishes.
- *i's version of petrification touch is currently active only for monster-on-monster combat; need to merge with my version for monster-on-pc combat.
- Pass party location to special in use special item context
- Fix set town visibility node (was checking wrong field and thus could not hide towns)
Special nodes:
- Town Hostile: change to Set Town Attitude
- Select PC node: option to select random PC
- Affect special nodes can now affect monsters
- Fix affect death node reviving non-existent PCs
- Affect Spells: Can remove spells, and can affect level 1-3 spells
- If Objects: Merged from If Barrels and If Crates
- If Species: Replaces If Cave Lore
- If Trait: Replaces If Woodsman
- If Statistic: Replaces If Enough Mage Lore
- Change Lighting: Can affect town's global lighting setting, player's light level, or both at once.
- Pointers! Actually, I'd already implemented the callbacks for setting and getting them, but they're now actually used, and the implementation has been tweaked a little.
- Campaign flags! Again, I'd already implemented them sorta, but I tweaked things and they ended up sort of halfway between the two implementations. Plus there's now a special node to set them.

Additional bits:
- Special queue now uses an std::queue instead of a basic array.
- Enum for town lighting levels
- Disease touch ability is now honoured for monster-on-monster combat
- See monster special context now passes the monster's location as the trigger location; also, removed the double-trigger from one circumstance.
- Along with the set town attitude change, there's now the possibility for making the town hostile to trigger a special node, which can cause the party to be slain.
- Select PC special node: option to select specific PC
- Spell IDs for use in shops and Affect Spell nodes have changed so that 0 is now the first level 1 spell, and so forth.
- add_string_to_buf can now auto-split the string over multiple lines, and the special node that uses it takes advantage of this
- Special node parser warns if a node type is missing a corresponding opcode
- Reserved "pointers" to access the special node's trigger location (this was *i's idea, but he never implemented it)
Bring up Get Items dialog when retrieving stored items from the next scenario, so that you can pick and choose which items to keep.
Also some bugfixes and stuff:
- Fix specials sometimes being run twice in a row
- Holding Control while clicking Create also makes a debug party (as an alternative to holding Command)
- Fix "How Many" popup being non-dismissible
- Reduce loading time spent on checking for missing opcodes
Clean up, fix, and tweak the spellcasting dialog
- Includes new status effect images for the forcecage and for hypothetical inverses of dumbfound and magic resistance, as well as icons for the whole-party statuses.
Don't create a new texture every time tiling is requested, though sadly this introduces a new issue
Various field/belt related stuff
- Remove all field booleans except quickfire and belt, which have been moved to cCurTown
- Alter and extend place_spell_pattern, to allow arbitrary damage types and to make it more clear in the code what's happening when it's called
- Delete fields.cpp file; a few things moved to locutils.cpp, but most are now part of cCurTown
- set_terrain function automatically updates belt present boolean if setting to a conveyor.
Clear out some unneeded casts
Beep beep
New special nodes:
- Town set attitude for affecting single creature, adapted from Windows code; technically redundant, but maybe handy
- If numeric response
- Print nums (for debugging)
- SDF arithmetic - add, subtract, multiply, divide, exponentiate
- Store random to SDF (adapted from Windows code)
- Display picture (inspired by Windows code, but the implementation is completely different and totally incompatible)
Expand If Statistic node to allow checking hp, sp, xp, skill points, etc
(Adapted from Windows code)
Expand if race/trait to allow for richer comparisons
(Adapted from Windows code)
Expand If Text Response node to allow specifying a prompt in the text respose dialog itself
Allow specials to trigger while in a boat.
Add a few item graphics
Implement right-click looking (adapted from Windows code)