This adds better exception handling ang logging to
_append_file_to_result helper in get_files. When reading
arbitrary file data and attempting to encode to utf-8
this can cause UnicodeDecodeError to be raised.
However, Armada will not skip over such files; it will
raise an exception with appropriate details instead.
Closes #195
Closes #196
Change-Id: Id7c32c17e351d1ffe042e3755c116c36b6380223
950c6012ab