show: implement underway view This is the beginning of a wip/smartlog view. It is basically a manually constructed (read: fast) revset function to collect "relevant" changesets combined with a custom template and a graph displayer. It obviously needs a lot of work. I'd like to get *something* usable in 4.2 so `hg show` has some value to end-users. Let the bikeshedding begin.

show: fix formatting of multiple commands Because we're formatting to RST, short lines wrap and there needs to be an extra line break between paragraphs to prevent that. In addition, the indentation in the old code was a bit off. Refactor the code to a function (so we don't leak variables outside the module) and modify it so it renders more correctly.

pycompat: import correct cookie module on Python 3 http.cookielib doesn't exist. http.cookiejar does and it contains the symbols we need. This fixes test failures on Python 3.

chg: respect environment variables for pager Previously chg runs the pager command without respecting its environment variables being told to use. This patch makes it so.

hgweb: add a link to followlines in descending direction We change the content of the followlines popup to display two links inviting to follow the history of selected lines in ascending (as before) and descending directions. The popup now renders as: follow history of lines <fromline>:<toline>: <a href=...>ascending</a> / <a href=...>descending</a>

hgweb: handle a "descend" query parameter in filelog command When this "descend" query parameter is present along with "linerange" parameter, we get revisions following line range in descending order. The parameter has no effect without "linerange".

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.