Bump the version string as well

When running the git hook, even though the appropriate config file is
found and processed, the exclude patterns and paths were not being
corrected to account for the temporary directory that we copy the files
into.

Related-to #223

If we handle an exception, or early exit, or really anything, we should
exit non-zero (and we used to). This was a minor oversight.

Closes #209
Closes #248

Do not print the source when provided with -q

When users specify any number of -q's on the command-line, we should not
show the source even if they have otherwwise configured Flake8 to do so.

Closes #245

See merge request !140

When users specify any number of -q's on the command-line, we should not
show the source even if they have otherwwise configured Flake8 to do so.

Closes #245

When we enable a plugin (when it's provided in the --enable-extensions)
plugin, we need to remove it both from the extended default ignore list
and the plain ignore list.

Closes #239

Change how we initialize our git hook application

Look for configuration files in the current directory while checking the
files in the temporary directory.

Closes #223 

Closes #210 

See merge request !136

In case the provided diff is empty, do not run checks against any files,
simply exit.

Closes #226