escape the readme blob in the tree view too

change got_open_blob_for_output to not look at the querystring 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".

require a commit id

render the READMEs in the tree view

use a detail for to show/hide the briefs' body

gotwebd: add actions to the blame view

gotwebd: make blame view work in text browsers While here pad line numbers with spaces instead of zeroes to match the blob view.

gotwebd: add actions in the diff view too

gotwebd: add patch action to serve diffs in plain text

gotwebd: add links for actions in the blob page positive feedback from Kyle Ackerman ok/tweak tracey@

gotwebd: introduce .page_header_wrapper to avoid style repetitions while here clean up some *_header id not used / not needed.

gotwebd: adjust blob line number for text browsers

gotwebd: add breadcums to navigate the tree/blob views ok tracey@

gotwebd: get rid of proc.[ch] proc.c really shines when there's a network of different types of processes, potentially with a various number of instances each, that needs to exchange messages. Gotwebd instead has a much simpler design, and using proc.c causes more overhead (/headaches) than it solves. So, this attempts to provide the same functionalities but with a much simpler implementation that fits gotwebd better. ok stsp@

gotwebd: render all the datetimes in a time tag fixes an unused variable that should have been dropped in previous commit too. ok stsp@