hgweb: remove unused/nonexistent filelogentry from atom/map filelog in atom style uses changelogentry to show commits, and atom/filelogentry.tmpl doesn't even exist.

hgweb: remove unnecessary CDATA markup in atom/branchentry.tmpl Since content is of type "text" (and is already escaped), using a CDATA section is not required. Looks like this was just an artifact of copying things from rss style in add2f9ddcfb5, because other entries in atom style don't use CDATA in such places.

hgweb: reindent rss/changelogentry.tmpl It was mixing tabs and spaces, and not in a good way. Indent style of other rss entries seems to be 4 spaces per level, so let's apply it here as well.

hgweb: remove a couple of superfluous spaces in rss style

py3: add tests in check-code to load modules from util.py The conditionalize imports are added in util.py and now we import modules from there. So adding tests so that someone in future can use that.

py3: conditionalize SocketServer import The SocketServer is renamed to socketserver in python 3