Large merge perf test.

Update some third-party copyrights

Fix doc comment formatting

Speed up AppVeyor builds.

AppVeyor build machines come with Python 2.7 and CMake 2.8 pre-installed and in the PATH.

repository: parse init.templatedir as a path

This is a path so we must use the path getter so we get the tilde
expansion done.

Update clar to d17c7f6

Handle 8dot3 filenames being disabled on Win32

for-each-ref example: initialize libgit2 in main

I don't get how it was working without git_libgit2_init() call. I run it
and libgit2 throws assertion somewhere in its internals. Now it works.

Updated commit with shutdown at the end.

Fixes for pedantry

README.md: Add Swift bindings "Gift"

structinit test: use %PRIuZ instead of %d for size_t

Tell user if libssh was not found

AppVeyor: Prettify build script

Fixes #2665

diff docs: update `git_diff_delta` description

64-bit Appveyor Builds

Clarified git_repository_is_empty() documentation

config: add parsing and getter for paths

Allow passing a NULL index to git_repository_set_index()

Fixed typo in git_repository_reinit_filesystem() documentation