* When a terminating newline is missing from the metric mapping configuration file, the last definition is not parsed at all. After this change the last 'METRIC_DEFINITION' in the file is equivalent to a newline (either between definitions or as the terminating newline).
* Update mapping, if we are reading the last line of the file. Otherwise we will append the mapping and lose the last label. Since we are updating the mapping in two different places a 'updateMapping' function was introduced.
* Added mapper test for config files without a terminating newline.
* Added another test case where multiple definitions are given without a final terminating newline.
* As suggested by @grobie, we should give an error when a terminating newline is missing. Updated tests accordingly.
