strip: move tree strip logic to it's own function This will allow external extensions to modify tree strip behavior more precisely.

manifest: remove unused property _oldmanifest The last use seems to have gone away in 7c7d845f8b64 (manifest: make manifestlog use it's own cache, 2016-11-10).

sslutil: reference fingerprints config option properly (issue5559) The config option is "host:fingerprints" not "host.fingerprints". This warning message is bad and misleads users.

py3: convert key to str to make kwargs.pop work in mq The keys are passed here and there as unicodes and our transformer make things bytes. Due to that, mq was not poped and this results in error on Py3. Here we abuse r'' to make that str on Python 3.

py3: convert kwargs' keys to str before passing in cmdutil.getcommiteditor

diff: add a fast path to avoid loading binary contents When diffing binary contents, with certain configs, we can show "Binary file <name> has changed" without actual content. That allows a fast path where we could avoid providing actual binary contents. Note: in that case we still need to test if two contents are the same, that's done by using "filectx.cmp", which could have its own fast path.

diff: correct binary testing logic This seems to be more correct given the table drawn in the previous patch. Namely, "losedatafn" and "opts.git" are removed, "not opts.text" is added. - losedatafn: diff output (binary) should not be affected by "losedatafn" - opts.git: binary testing is helpful for detecting a fast path in the next path. the fast path can also be used if opts.git is False - opts.text: if it's set, we should treat the content as non-binary

diff: draw a table about binary diff behaviors The table should make it easier to reason about future changes.

diff: use fctx.size() to test empty fctx.size() could have a fast path that does not require loading content.

diff: use fctx.isbinary() to test binary The end goal is to avoid calling fctx.data() when unnecessary. For example, if diff.nobinary=1 and files are binary, the expected behavior is to print "Binary file has changed". That could avoid reading fctx.data() sometimes. This is mainly to enable an external LFS extension to skip expensive binary file loading sometimes (read: most of the time with diff.nobinary=1 and diff.text=0), without any behavior changes to mercurial (i.e. whether a file is LFS or not does not change any behavior, LFS could be 100% transparent to users).