add an error message when parsing nested #defines in WML

This doesn't work, so it's better to give an actual message
rather than silently fail.

This is tangentially relevant to feature request #21343, I added
a code comment at the appropriate place where we might fill that
request.
fix assertion failure in unit_display.cpp, bug #22305

It was a simple programmer error I made in commit:
750e770c62d3498bbc78f3eda60c5f41d6a03b39
update changelog
replace segfault with assert.
fixup whitespace issues
move extract_summary_from_config fcn to private namespace

Since it is only used there anyways
fixup how extract_summary_from_config stores map_data

This forward ports part of e7eb08d0cd2d57b55bf084b669fbeec8d283db33
which was fixing bug 22086 in 1.12 branch.
carry forward some debugging info from 1.12 bugfix 22086

from 1.12 branch, commit e7eb08d0cd2d57b55bf084b669fbeec8d283db33
add some debugging for game_classification when loading

Carry forward some debugging info. This code was introduced
in 1.12 branch in bug fix for 22086, commit

e7eb08d0cd2d57b55bf084b669fbeec8d283db33
update changelog
remove some dead code "fill_mplevel_config"
Updated changelog
fixup [filter_vision] tags

This is the master version of PR #237, with unit tests.
add [has_ally],[has_enemy] tags for standard side filter

Unlike [allied_with] and [enemy_of], these will match if only if
there is *any* ally or enemy matching the filter. The other versions
of the tag match only if all sides matching the filter are
allied / opposed.

This commit also adds a unit test that checks that it works as
expected.
update changelog
Merge branch 'has_ally_master'

Conflicts:
	wml_test_schedule
update changelog
Merge branch 'master' of git://github.com/wesnoth/wesnoth

Conflicts:
	changelog
updated French translation
remove executable flag from french manual images