url: merge BetterHTTPS with httpsconnection to get some proxy https validation

tests: test https through http proxy These tests fails for me with Python 2.6(.nothing)

url: always create BetterHTTPS connections the same way

url: refactor BetterHTTPS.connect

url: refactor _gen_sendfile

url: remove test for self.ui in BetterHTTPS We use self.ui unconditionally anyway so we would have noticed if it in some cases wasn't set.

tests: update ssl requirement for test-https.t hgweb requires OpenSSL for serving https.

subrepos: prompt on conflicts on update with dirty subrepos Consider a repository with a single subrepository. The changesets in the main repository reference the subrepository changesets like this: m0 -> s0 m1 -> s1 m2 -> s2 Starting from a state (m1, s0), doing 'hg update m2' in the main repository will yield a conflict: the subrepo is at revision s0 but the target revision says it should be at revision s2. Before this change, Mercurial would do (m1, s0) -> (m2, s2) and thus ignore the conflict between the working copy and the target revision. With this change, the user is prompted to resolve the conflict by choosing which revision he wants. This is consistent with 'hg merge', which also prompts the user when it detects conflicts in the merged .hgsubstate files. The prompt looks like this: $ hg update tip subrepository sources for my-subrepo differ use (l)ocal source (fc627a69481f) or (r)emote source (12a213df6fa9)?