* Add default keys to settings template #1302
* Allow querying key module settings entries #1302
* Move key bindings to settings #1302

Still in a proof-of-concept stage.
Does not yet handle input by keycode or any modifier keys.
Also needs a way to query all settings of a certain module.
* Also store hotkey key values (stringified) in settings file #1302

This uses yet another __dict__ access which i am not very happy about.
I considered storing the plain keycode as int, but that would not be
recognizable for players trying to edit these settings on their own.

Currently these four keys will trigger the KeyError in question: -+,.
* Make action "increase game speed" only have one assigned hotkey

This effectively reverts fdf07d0e348fd9495270a6ab8c77e24c9d66e955.

With the hotkey design approach I took for now, we do look at actions
as main source of information when configuring the interface, not keys.
Internally we still store this information keyed by the associated key.
This means that while the same action xml-technically may be assigned
to multiple actions, only one of them would be recognized (unordered).

For devices where + and = would not send the same keycode (for me they
do) and the default + is inconvenient (such as US keyboard layouts),
this is an excellent opportunity to try and reconfigure the hotkey :)
* Refactor build_help_strings

I am guilty of calling horizons.main for the greater good :(
* Display currently available keys when clicking on help label

Uses some trickery to make sure no weird keys show up and are selected.
* Fix problems with hardcoded SHIFT hotkey

Since our mousetools still manually poll for isShiftPressed,
this is the best we can do for now.
* Allow accessing popup attributes (headline, message)
* Hotkeys can now be changed on runtime

Partially ugly code, sorry about that.
* Minor whitespace fix
* Store hotkeys in upper case

Was inconsistent with the fife keys such as DELETE.
* Read hotkey settings from settings file #1302
* Interface to query default hotkeys from settings

Also removes the keyname mappings of +-,. -- while a nice idea on paper,
this caused too many issues everywhere to be a reasonable design choice.

Introduces a validation for key input from user settings files.
If we detect invalid keys, this action is reset to the default key.

New feature: Clicking on the line that states the current and default
key will also assign the default key to the current action.
First working version of the new map editor.
Delete the old editor plugins.
editor: Allow placing tiles continusly
editor: Allow changing multiple tiles at once

A ugly widget allows choosing between 3 different brush sizes (circle
form).
editor: Small fixes and a bit of cleanup
editor: Show tile highlight when placing tiles