Log Message:
Update xchm to 1.2.

Changes since 1.0:
  - Added TW translation.
  - Fixed bookmarks save on application exit bug.
  - Added support for the <SPAN> HTML tag.
  - Better icons for the contents tree control items.
  - Added Chinese translation.
  - Improved the language detection system and non-Latin character
    sets display in Unicode builds.
  - Fixed Cyrillic characters display in Unicode builds.