[NEW_FEATURE] Add 2 new plugins APIs: NPPM_GETEDITORDEFAULTBACKGROUNDCOLOR & NPPM_GETEDITORDEFAULTFOREGROUNDCOLOR
[NEW_FEATURE] Make internal docking dialog match/follow the selected theme's background and foreground colors.

git-svn-id: svn://svn.tuxfamily.org/svnroot/notepadplus/repository/trunk@1259 f5eea248-9336-0410-98b8-ebc06183d4e3