Amend a WML comment for accuracy
Drop Wesnoth 1.10.x compatibility code
Drop Wesnoth 1.11.0 compatibility code
Drop compatibility code handling pre-1.11.6 ellipse semantics
Drop ABILITY_CAPTION and WEAPON_SPECIAL_CAPTION used for 1.11.0 compatibility
Drop Wesnoth 1.11.0/1.11.1 compatibility code
Drop Wesnoth 1.11.0 - 1.11.4 theme UI compatibility code
Drop Wesnoth 1.11.0 - 1.11.7 terrain aliases compatibility code
Drop Wesnoth 1.11.0 - 1.11.7 theme UI compatibility code
Consolidate maps using WESNOTH_1_12_MAP_OVERLAY (1.10.x compatibility)
Drop WESNOTH_1_12_MAP_OVERLAY macro used for 1.10.x compatibility
Drop workarounds for mainline bugs #20350 and #20351, used for < 1.10.6
Drop animation WML macro compatibility code for 1.11.0 - 1.11.6
Add optional may_ignore= (def. yes) attribute to [bug]
Raise minimum version requirement to 1.11.11

Versions < 1.11.11 that aren't 1.11.9 are not allowed to continue past
the [bug] message the version check triggers.
Drop compatibility code used for Wesnoth 1.11.0 - 1.11.7
Replace version checks with a single HAVE_SAVE_GOLD_ASPECT_BY_DEFAULT macro

This is used to signal when the Wesnoth version in use has the AI
recruitment_save_gold aspect turned on by default.

At this time, the versions for which we define this symbol are those in
the [1.11.7, 1.11.9) set. I believe someone said something about
re-evaluating the recruitment_save_gold impact on 1.13.x, so this macro
should stay regardless of any version compatibility changes affecting
1.11.x.
Allow Wesnoth 1.11.8 as an unsupported but working version