localrepo: improve docstring for revset methods revs() doesn't return a list. Also document what its arguments do. Also clarify that set() is just a convenience wrapper around revs().

revlog: improve documentation There are a lot of functions and variables doing similar things. Document the role and functionality of each to make it easier to grok.

demandimport: don't enable when running under PyPy On demand importing doesn't work with PyPy for some reason. Don't honor requests to enable demand importing when running under PyPy.

ui.write: don't clear progress bar when writing to a buffer ui.write() has 2 modes: buffered and unbuffered. In buffered mode, we capture output before writing it. This is how changeset printing works, for example. Previously, we were potentially clearing the progress bar for every call to ui.write(). In buffered mode, this clearing was useless because the clearing function would be called again before actually writing the buffered data. This patch stops the useless calling of _progclear() unless we are actually writing data. During changeset printing with the default template, this removes ~6 function calls per changeset, making changeset printing slightly faster. before: 23.76s after: 23.35s delta: -0.41s (98.3% of original)

test-resolve: fix '--tool f' invocation for Windows Windows can't invoke a python script directly, so invoke sh.exe instead. According to sid0, the output changes are due to the fact that 'f' is no longer being passed all of the args that it was, but these changes aren't essential to the test [1]. [1] https://selenic.com/pipermail/mercurial-devel/2015-November/075768.html

util.datestr: use divmod() We were computing the quotient and remainder of a division operation separately. The built-in divmod() function allows us to do this with a single function call. Do that.