Blame timeout

[nllptr]

To avoid heavy blame operations from taking too much time, a timeout should be implemented that aborts the blame command if it exceeds a configurable amount of time.

Suggested configuration vairable and its default value:
blameTimeout = 20000 ms or 20 s

UPDATE: After testing with commits that should generate a significant load, the blame command still doesn't take that long to run. This issue will be deferred until the blame code is reworked to look at more lines.

[nllptr]

Will try to write a script that creates a nice commit history to test with. And I only wrote this comment to get a green dot :)

EDIT: Ok, so apparently you don't get green dots for commenting on issues. Anyhow, there is a program for generating tons of commits (https://github.com/nllptr/masscommit)