Refactored trash terrain gfx macros into a separate file, removed TRI prefix

The macro-less portions of these terrain graphics rules are now the
TRASH_A and LITTER_BASE macros. I tried to the best of my ability to
understand how they are supposed to work together, so this is the naming
scheme and parameter set I found to be the most optimal:

    #define TRASH_A TERRAIN PROB IMAGESTEM
        Covers the first and second rules, which are used on a single
        terrain pattern.
    #define LITTER_BASE TERRAIN IMAGESTEM
        Covers the third rule, which affects both trash terrains.
Move rules for trash terrains up to where they belong in terrain-graphics.cfg
Update changelog for the WML error report improvements
Update RELEASE_NOTES
scons: hotkey/hotkey_preferences_display.cpp is not special

The only reason game_preferences_display.cpp receives special
considerations is that it depends on a preprocessor symbol that we don't
want to trigger a full rebuild every time the relevant scons option is
changed. hotkey_preferences_display.cpp does not use that symbol
(WESNOTH_PREFIX).
Move hotkey/hotkey_preferences_display.cpp from libwesnoth.a to main sources

Oops.
gui2/taddon_description: Let the description area grow horizontally

Let it grow to fill the space available when it's greater than the
description box's requested size (e.g. for very short descriptions).
gui2/tchat_log: Use 'description' scroll_label type for the log
gui2/tchat_log: Let the log scroll_label grow horizontally
gui2/tchat_log: Hack to set a minimum cell size to 200x250

Because this window many contain a lot of text in both directions,
having it change size dynamically every time the log page is switched or
a new text filter is entered can be extremely annoying for the player.

Setting the scroll_label's parent (now ancestor) cell's minimum size to
something that isn't 0x0 mitigates the issue to some extent. Better than
nothing, I guess.

(Tested with a screen resolution of 800x480.)
SotBE S14: map changes for rebalancing

Take about 40% of the villages off the map and change the paths in the
southeastern part of the map a little.  The latter is done so that the
eastern enemy focuses more on Kapou’e rather than the southeastern
ally, making the AI leader surviving less dependent on luck.
SotBE S14: balancing adjustments to turns, gold, income
Rewrote 'Training the Ogres'
Fixed some screwups
EI S8 (Training the Ogres): add custom AI for the ogres
Remove a no longer existing Doxygen param.
Adds -Wold-style-cast to the CMake strict flags.
AnimationWML: add warning for mismatched leading zero paddings in square bracket expansions.
SotBE S15: map changes for balancing

Taking a number of villages off the map.
SotBE S15: balancing adjustments to turns and gold