Added support for project:issue-number queries

Added support for project specific issues (Chromium is the still default when the project name is omitted). b:v8:989, b:skia:822 and so on.
This is not optimized at all (it is called several times per query - creating an object every time - instead of being cached and re-used), but so was the previous code (though it was much simpler).
This will be a conflict (I changed it to 9.1 recently, noticed a bug). 10.0 is still correct. If I'm able to resolve this myself I'm happy to do so and accept the pull request, but I don't want to screw something up. I presume you need to do the rebasing.