Performance and reliability fixes

[raspy]

As a follow-up for #1, I would like to submit my changes. These were mostly around performance, but also two bugfixes:

• only 100 files per commit were checked,
• pattern matching behavior changed in 3.1.0.

Since my use case was to prevent large files uploaded (that should go into LFS), the first limitation was a major drawback that allowed large files to slip through.

As for performance, I have tested scenarios with file size hook with two different patterns set:

• pushing 3 branches (2244, 1470 and 2130 new commits respectively) with some commits changing over 2000 files - hook time inspection: 4.5 seconds (reduced from 55 seconds),
• pushing whole repository (2868 branches, 1.8 GiB in total) - hook time inspection: 89 seconds (previously hook was killed by Bitbucket after 3 hours of running).

Every commit that introduced a performance change is accompanied with a longer description why the change was made and what was the result.

Please feel free to review and accept unless there are concerns. Should you have any questions, please don't hesitate to ask.

[christiangalsterer]

Thank you for your contribution and submitting a PR. Looking at the numbers this would be really a cool improvements. I'm travelling for the next couple of days hence it will take me a few more days to look into it.

[christiangalsterer]

Locally merged