merge from default

added stubs for two wrapper utils to get build (cpp) macros and metadata macros -- WIP

fix some merge glitches

merge commit

refactoring usage for getting variant.hrh and compiler preinclude macros. Now should use ISymbianContext both for preprocessed results and getting the IPath to the file. Removed start-up checks for Perl version.

some prototyping for linked project root

mark abld-specific methods as deprecated