Add support for Boost.Build V2.

* process_jam_log.cpp:

 (test_path_to_library_name): Handle a situation where a directory
 has some tests and subdirectories for a different library. Example
 is libs/functional/function_test and libs/functional/hash/test/*.

 (parse_skipped_msg): Extract duplicated code...
 (parse_skipped_msg_aux): ... here. Also add support for V2 target naming.
 
 (main): Handle --v2 option

* compiler_status.cpp
  (find_bin_path): New function for logic that was repeated in two places.
     Add support for V2.