Limit pygit2 gitfs provider transports

pygit2 doesn't yet support ssh transports properly, as seen here:

http://stackoverflow.com/questions/20956895/how-do-i-set-ssh-credentials-for-libgit2-libssh2

This commit limits pygit2 to http://, https://, and file:// URIs. Once a
compatible pygit2 version is released, we can do version checking and
allow ssh-based transports for pygit2 on supported versions.
Add more state vs module clarification
Merge pull request #9619 from terminalmage/pygit2-ssh

Limit pygit2 gitfs provider transports
Merge pull request #9623 from basepi/moduledocs

Add more state vs module clarification
Updated windows docs with a quick note to mention that the installers will install deps.
Fix versionadded:: for filter_by() "default=" parameter

This parameter has been introduced by commit dbfe790a, which has not
been merged in 0.17 branch. Only in 2014.1.
Merge pull request #9631 from tmartinfr/fix-doc-filter_by

Fix versionadded:: for filter_by() "default=" parameter
Fix version naming.
Merge pull request #9630 from gravyboat/develop

Windows installation doc update explaining deps will be installed.