Merge with stable

dispatch: don't mangle ImportError abort messages Previously, Mercurial assumed that the last word of the string representation was the name of the moduled that was imported. This assmption is incorrect, despite being true for the common case of an exception raised by the Python VM. For example, hgsubversion raises an ImportError with a helpful message if the Subversion bindings were not found. The final word of this message is not meaningful on its own, and is never the name of a module. This patch changes the output printed to be a simple stringification of the exception instance. In most cases, this will be `abort: No module named X!' rather than `abort: could not import module X!'. No functionality change; all tests pass.

relink/progress: correctly handle the no file to relink case

Merge with stable

commands: refactor diff --stat and qdiff --stat `opts['unified'] = '0'` can be replaced by `diffopts.context = 0`.

mq: fix opts['unified'] = '0' to take effect when qdiff --stat `opts['unified'] = '0'` tries to reduce the number of lines to be processed by patch.diffstat, but here it does not affect diffopts, thus it does not make sense. Instead, we can change `diffopts.context` directly. Added test case for qdiff --stat.

showconfig: show rc paths with --debug

tags: return tags in sorted order This makes log and summary have less arbitrary tag ordering and also groups similar tags together, such as the mq tags.