revset: add a 'descend' argument to followlines to return descendants This is useful to follow changes in a block of lines forward in the history (for instance, when one wants to find out how a function evolved from a point in history). We added a 'descend' parameter to followlines(), which defaults to False. If True, followlines() returns descendants of startrev. Because context.blockdescendants() does not follow renames, these are not followed by the revset either, so history will end when a rename occurs (as can be seen in tests).

context: add a blockdescendants function This is symmetrical with blockancestors() and yields descendants of a filectx with changes in the given line range. The noticeable difference is that the algorithm does not follow renames (probably because filelog.descendants() does not), so we are missing branches with renames.

url: support auth.cookiesfile for adding cookies to HTTP requests Mercurial can't currently send cookies as part of HTTP requests. Some authentication systems use cookies. So, it seems like adding support for sending cookies seems like a useful feature. This patch implements support for reading cookies from a file and automatically sending them as part of the request. We rely on the "cookiejar" Python module to do the heavy lifting of parsing cookies files. We currently only support the Mozilla (really Netscape-era) cookie format. There is another format supported by cookielib and we may want to consider using that, especially since the Netscape cookie parser can't parse ports. It wasn't immediately obvious to me what the format of the other parser is, so I didn't know how to test it. I /think/ it might be literal "Cookie" header values, but I'm not sure. If it is more robust than the Netscape format, we may want to just support it.

httpconnection: allow a global auth.cookiefile config entry This foreshadows support for defining a cookies file.

util: make cookielib module available In preparation for supporting sending cookies on HTTP requests.

crecord: avoid setting non-existing SIGTSTP signal on windows (issue5512) Windows do not have a SIGTSTP so we avoid setting the handler if the signal is unknown.

crecord: ensure we reinstall the SIGTSTP handler Previous, exceptions would prevent the reinstallation of the signal.

crecord: avoid setting non-existing signal SIGWINCH on windows Windows do not have a SIGWINCH so we avoid setting the handler if the signal is unknown.

crecord: ensure we reinstall the SIGWINCH handler Previous, exception in _main(...) would prevent the reinstallation of the signal.

crecord: extract most of 'main' into a sub function There are some setup and cleanup necessary around the main code, that setup/cleanup code needs multiple adjustments so we extract the core code into its own function first for clarity.