use File.exist? instead of File.exists?
remove unused variables
Using https instead of http

Use https://github.com instead of http://github.com inside the README.md template.
Merge pull request #2870 from hsbt/remove-warnings

Remove warnings
Debug resolver once the find_conflict is done

The current code throws an error if we're using
DEBUG_RESOLVER=1 and it wasn't able to find any gem
to rewind to, thus returning nil.
Always pass --quiet to git clone.

Fixes #2707.
Inline the clone_command variable.
Merge pull request #2875 from TimMoore/fix-specs-with-new-git

Always pass --quiet to git clone.
Merge pull request #2871 from tbuehlmann/patch-1

Using https instead of http