Skeleton Cursor implementation.
Moved SourceLocation out into separate files
Added cursor method to TranslationUnit
Changed to use tabs instead of spaces.
Added location method to diagnostic
Added simple source_location_spec test for file, line, column attrs from diagnostic
Changed source_location to use clang_getExpansionLocation as clang_getFileLocation does
not exist in 3.2
Changed to use ':ptr_data, [:pointer, 2]' in source_location and diagnostic.
Extensions to cursor class - added first attempt at 'visitor' function
taking a block.
Extended the tests for cursor.
Merge pull request #1 from GazCMarsh/master

Skeleton Cursor implementation