the implicit dependency on the various variables inside the querystring makes reusing the code in got_operations.c a bit harder. Accessing a blob in the tree view for instance requires a few workaround. Instead, just take the folder^W directory, file and commit id as arguments, so they can be easily changed without hacks in the proper places. While here, support passing a NULL commit to mean "HEAD".

While here pad line numbers with spaces instead of zeroes to match the blob view.

positive feedback from Kyle Ackerman ok/tweak tracey@

ok tracey@

Diff from Kyle Ackerman. tracey@ and I likes it.

while here clean up some *_header id not used / not needed.