Moved rand_string to unittest_utils.
Made parse_time not have such logger.cc-specific exception-throwing behavior.
Made directory_lock_t destructor be noexcept(false).
Fixed calls and includes in unit tests.
Removed unused functions ptr_in_byte_range and range_inside_of_byte_range.
Made remove_directory_recursive not throw an exception.  Removed remove_directory_exc_t.

Nothing was catching the exception, which seemed to know that its
own error message was for a fatal error.  Also, if we did catch
it, there would be a memory leak because we throw from inside
the callback of nftw.
Removed exception specifier recently added to ~directory_lock_t.
Flipped the boolean treatment of parse_time in logger.cc.  Made uuid.cc compile on some systems.
Merge branch 'sam_stupid' into next