[libclang] Add Logger::operator<< overloads for CXCursor and FileEntry.
[libclang] When calling the function of CXCursorAndRangeVisitor, don't forget to
stop visitation if it returns CXVisit_Break.
[libclang] Introduce clang_findIncludesInFile, that can be used to retrieve all #import/#include directives in a specific file.

It passes to the visitor, that the caller provides, CXCursor_InclusionDirective cursors for
all the include directives in a particular file.