Pydriller

1. Support the analysis of multiple repos
2. Support remote repos

PyDriller now calculates structural metrics of every file changed in a commit: the modification object now has this info.

Fix issue on resetting the repository.

Contributor: Ledenel

Speed improvement in calculating the bug inducing commits.

Speed improvement

New function "get_commits_last_modified_lines" that applies SZZ to retrieve the list of the commits that last modified some lines.

Plus, is much faster than before since I fixed a bug in the logging of RepositoryMining. Now it analyses ~60 commits per second.