Update plugin.xml and readme.md to prepare for release
Enable generalized color scheme support

Use DefaultLanguageHighlighterColors to get support for all default
color schemes (plus newer custom schemes which are correctly defined).

See http://confluence.jetbrains.com/pages/viewpage.action?pageId=49463468
for more details.
Update icon to play nice with dark theme
Update plugin.xml to prepare for release
Update version to ensure highlighting updates

DefaultLanguageHighlighterColors is only available in later versions of
IDEA.  Update dependency in plugin.xml to ensure we have access to them.
Fix typo in plugin.xml
Stub out new methods in PropertiesComponentStub
Fix duplicate calls introduced by rebase merge
Update plugin.xml for release