Alter Order of Exceptions in Handling Routine

IOError derives from EnvironmentError, therefore we should call the
more specific exception first to prevent 'greedy handling' of
exceptions
Fix unreference 'err_str' and the subprocess run of ctags
Merge pull request #171 from xdmiodz/bug/168

Fix unreference 'str_err' and the subprocess run of ctags
Update Messages for Package Control