CIndex:

- Remove unused (and unimplemented) clang_getDeclarationName().
- Remove unused (and unimplemented) clang_getEntity().
- Add clang_getEntityFromDecl(): maps from a CXDecl to a CXEntity)
- Add clang_getDeclaration(): maps from a (CXEntity, CXTranslationUnit) to a CXDecl).

llvm-svn: 93209