just annoying when there are directories whose name contains a space
within the src/ directory

see #227

Notice that without the fix this test fails.

backport of 4a96057e

thanks to @valsson

Check first if astyle is present. In this way, when astyle is not compiled,
we get a single error instead of one error per file.

Thanks @hanatok!

Also this after a discussion with @marcodelapierre

thanks to @marcodelapierre

This reverts commit 2128bada.

Giving false positive in master branch - no idea why and cannot debug it

This reverts commit 5ba9eb93.

More efficient on travis-ci

When doing plumed patch -e gromacs2016.5 a match with e.g. gromacs2016.4
will be accepted (and issue a WARNING). Useful for automatized patching
procedures.

For instance, in gromacs-plumed package of MacPorts it won't be necessary
to synchronize the Portfile with the exact plumed version.

(cherry picked from commit ae6c8ee4)

This will decrease the number of pull requests from PlumedBot.

Currently, everytime a file is updated and someone forgets to run
headers.sh, the headers are outdated. With this change, this will happen
once per year. PlumedBot will thus mostly fix erroneous copyrights
(rarely happening).