setup: update a comment that blamed py26 for a Windows workaround

i18n: drop a py25 conditional I'm not sure how to test this one. `make update-pot` spews all kinds of warnings, though it did before this change too.

perf: ensure HGRCPATH is exported on Windows After dropping the garbage collector hack, `hg perfstartup` started yelling about not being able to import the evolve extension, which I have in my user config. Launching `env` shows that an empty HGRCPATH isn't exported to the environment. Since `env` doesn't quote, I have no idea if the variable is trimmed, but Mercurial doesn't complain when processing it.

test-status: glob fixes for Windows

plan9: drop py26 hacks

revset: fix negative ancestor spec to not return changectx objects The order was unstable because of this.

obsolete: use ProgrammingError over assert for volatile set registration We have ProgrammingError now.

strip: remove a redundant setting of hookargs bundle2.applybundle() will set both 'source' and 'url'.

unbundle: move streamclone error case away from bundle[12] cases The bundle1 and bundle2 cases are more similar, and having the streamclone case in between is distracting.

bundle2: use "else" instead of checking condition again

wireproto: update reference to deleted addchangegroup() Thanks to Yuya for catching this.

template: add predecessors template Add a 'predecessors' template that returns the list of all closest known predecessors for a changectx. The elements of the list are row changectx node id formatted by default as short nodes. The "closest predecessors" are the first locally known revisions encountered while, walking predecessors markers. For example: 1) If a (A, (B)) markers exists and both A and B are locally known A is a closest predecessors of B. 2) If a (A, (B)) and (B, (C)) markers exists and only A and C are known locally, A will be the closest precursors of C. This logic respect repository filtering. So hidden revision will be skipped by this logic unless --hidden is specified. Since we only display the visible predecessors, this template will not display anything in most case. It makes a good candidate for inclusion in the default log output. I added a new test-file for testing the precursors in various scenarios. This test file will also be used for the successors template. A new "obsutil" module has been added to start gathering utility function outside of the large obsolete.py module.

commit: select template by spec.ref name And load all templates defined in [committemplate] since the selected template is no longer be named as 'changeset'.

commit: do not look up committemplate in template paths (BC) From 5375ba75df40 and de5cee8ba088, I don't think the current behavior is intended. Commit templates should be processed as literal templates.

formatter: always store a literal template unnamed Now spec.ref should be '' if spec.tmpl is specified. Since spec.ref is the option to select the initial template to be rendered, it doesn't make sense to store the given literal template as spec.ref.

formatter: load templates section like a map file Since a map file has another level to select a template (spec -> mapfile -> topic), this isn't exactly the same as how a map file works. But I believe most users would expect the new behavior. A literal template is stored as an unnamed template so that it will never conflict with the templates defined in [templates] section.