* wesnoth-mode.el: Updated changelog; fixed trailing whitespace and indented

* wesnoth-mode.el: Updated changelog; fixed trailing whitespace and indented
  correctly.
  (wesnoth-define-blocks): New variable.
  (wesnoth-font-lock-keywords): Minor clean-up for `wesnoth-preprocessor-face'
  faces.
  (wesnoth-element-closing, wesnoth-element-opening, wesnoth-element): Minor
  regexp clean-up.
  (wesnoth-indent): Rewritten.  Slightly more efficient; more consise;
  simpler.  No longer moves to the end of the line.
  (wesnoth-within-define): Rewritten.  Uses cache of macro definition blocks.
  (wesnoth-find-macro-definitions): New function.  Return information
  regarding macro definition blocks.
  (wesnoth-indent-region): New function.
  (wesnoth-determine-context): Renamed from `wesnoth-ensure-define-separate'.
  Rewritten to use macro definition cache and return more specific information
  regarding the context.
  (wesnoth-mode): Set `indent-region-function' to `wesnoth-indent-region'.