Merge with mpm

merge: implement --tool arguments using new ui.forcemerge configurable ui.forcemerge is set before calling into merge or resolve commands, then unset to prevent ui pollution for further operations. ui.forcemerge takes precedence over HGMERGE, but mimics HGMERGE behavior if the given --tool is not found by the merge-tools machinery. This makes it possible to do: hg resolve --tool="python mymerge.py" FILE With this approach, HGMERGE and ui.merge are not harmed by --tool

tests: fix up changed output

revset: disable subset optimization for parents() and children() (issue2437) For the boolean operators, the subset optimization works by calculating the cheaper argument first, and passing the subset to the second argument to restrict the revision domain. This works well for filtering predicates. But parents() don't work like a filter: it may return revisions outside the specified set. So, combining it with boolean operators may easily yield incorrect results. For instance, for the following revision graph: 0 -- 1 the expression '0 and parents(1)' should evaluate as follows: 0 and parents(1) -> 0 and 0 -> 0 But since [0] is passed to parents() as a subset, we get instead: 0 and parents(1 and 0) -> 0 and parents([]) -> 0 and [] -> [] This also affects children(), p1() and p2(), for the same reasons. Predicates that call these (like heads()) are also affected. We work around this issue by ignoring the subset when propagating the call inside those predicates.

check-code: warning and fixes for whitespace in unified tests

hgweb: use Pythons ssl module for HTTPS serve when using Python 2.6 or later pyOpenSSL apparently doesn't work for Python 2.7 and isn't very actively maintained. The built-in ssl module seems like a long-term winner, so we now use that with Python 2.6 and higher.

hgweb: refactor all pyOpenSSL references into one class

gendoc: added styling for extension TOC Uses CSS3 columns for the list of extensions, so it is not just a long list of extension names.

gendoc: automatically create help for default extensions. Adds a section in the hg.1 manpage and corresponding hg.1.html file. Each extension is listed with its module docstring, followed by the commands defined by that extendsion. Creates help for extensions by extracting doc strings from the extension modules and its commands.

gendoc: dedent documentation from docstrings When getting docstrings from the source they are indented to look good in the code. This indentation interferes with how the text is parsed by rst. Therefore this indentation is removed.