Remove IDE-specific files from .gitignore and git

[krichter722]

Remove IDE-specific files from .gitignore which are supposed to be managed in .git/info/exclude

[coveralls]

Coverage decreased (-0.04%) to 70.124% when pulling 196ae8b on krichter722:gitignore into 367da7d on tools4j:master.

[terzerm]

Not sure what problem you are trying to solve. We are happy the way this is currently configured with idea files ignored (except two files) and checked in to .gitignore.

If you describe the problem in a new issue we may decide to come back to this. As it stands I have to reject it as I am not understanding the motivation for it.

[krichter722]

The project is more easy to maintain if it depends on the build tool (and eventual plugins) only. This is achieved by keeping all IDE-specific files out of the SCM. Furthermore you keep the project open to developers who don't want to develop with a specific IDE which is unnecessary if it depends on the build-tool only. Codestyle only makes sense to be maintained with static analysis tools like checkstyle, not a formatter (you can offer a file that pleases checkstyle for different IDEs outside the source root). There's currently no problem, but there might be in the future.