Changes for non-github projects like bitbuckets

Hi

I've been constrained to make some changes to be able to generate log working with bitbucket for managing 2 differences:
- the commit are set in **/commits/** in bitbucket instead of **/commit/**
- issues are logged in a specific JIRA URL (in my case)

I've also added a "perf" section, and it looks like the "refactor" section was not generated. 

I hope my code respects the existing code. If no do not hesitate to ask me for changes, to iterate till the changes can be integrated.

Thanks