basefilectx: move isexec and islink from memfilectx This will be used in the future for creating memctx objects from other store-type objects, such as a patch store or even another context.

tests: fix pyflakes test whitespace breakage

pushkey: wrap pushkey phase movement in a transaction Phases are not yet inside the transaction, but we need to prepare for it. So we wrap the phase movement inside a transaction.

push: wrap local phase movement in a transaction Phases are not yet inside the transaction, but we need to prepare for it. So we wrap the phase movement inside a transaction.

phase: wrap `hg phases` phase movement in a transaction Phases are not yet inside the transaction, but we need to prepare for it. So we wrap the phase movement inside a transaction.

mq: wrap qimport phase movement in a transaction Phases are not yet inside the transaction, but we need to prepare for it. So we wrap the phase movement inside a transaction.

mq: wrap qfinish phase movement in a transaction Phases are not yet inside the transaction, but we need to prepare for it. So we wrap the phase movement inside a transaction.

tests: change some #ifs to #requires

tests: replace exit 80 with #require

run-tests: add #require to abort full test This allows nuking a bunch of ugly hghave || exit 80 lines.

run-tests: add support for xunit test reports The Jenkins CI system understands xunit reports natively, so this will be helpful for anyone that wants to use Jenkins for testing hg or extensions that use run-tests.py for their testing.

contrib: add check-commit hook script to sanity-check commits