Document IndexMatchedPath

Since rust-lang/rust#19553, missing_docs checks typedefs too.
Update to rust master
Fix git_filemode_t values.
Merge pull request #25 from Trundle/fix_git_filemode_t_values

Fix git_filemode_t values.
Merge branch 'document-IndexMatchedPath' of https://github.com/cuviper/git2-rs into cuviper-document-IndexMatchedPath

Conflicts:
	src/index.rs
Update libgit2 dep and don't bulid debuginfo

In debugging a segfault on win32 with gcc 4.9.2, I ended up updating the libgit2
dep as well as figuring out that the RelWithDebInfo profile causes a segfault
while Release does not! This looks to be a bug in gcc 4.9.2, but it'll be tough
to track down, so let's just stick with this for now.
Choose cmake profile based on cargo profile
Fix API definition of git_remote_download
Merge remote-tracking branch 'upstream/master'

Conflicts:
	libgit2-sys/libgit2