Changed context_lines and interhunk_lines to uint32_t to match struct s_xdemitconf
netops: return GIT_ECERTIFICATE when it fails the basic tests

When we first ask OpenSSL to verify the certfiicate itself (rather
than the HTTPS specifics), we should also return
GIT_ECERTIFICATE. Otherwise, the caller would consider this as a failed
operation rather than a failed validation and not call the user's own
validation.
merge: talk about the merging state after git_merge()

Since it's not necessarily obvious, mention the merging state and how to
clear it.
remote: fix tagopt test

An anonymous remote wouldn't create remote-tracking branches, so testing
we don't create them for TAGS_ALL is nonsensical. Furthermore, the name
of the supposed remote-tracking branch was also not one which would have
been created had it had a name.

Give the remote a name and test that we only create the tags when we
pass TAGS_ALL and that we do create the remote-branch branch when given
TAGS_AUTO.
remote: unify the creation code

The create function with default refspec is the same as the one with a
custom refspec, but it has the default refspec, so we can create the one
on top of the other.
Make the Visual Studio compiler happy
Fix segmentation fault observed on OpenBSD/sparc64

A non-readable mapping of a file causes an access violation in
the pack tests. Always use PROT_READ to work around this.
Merge pull request #2684 from jacquesg/openssl-windows

Make the Visual Studio compiler happy
Merge pull request #2685 from libgit2/cmn/mmap-readable

Fix segmentation fault observed on OpenBSD/sparc64
Merge pull request #2680 from libgit2/cmn/invalid-cert-return

netops: return GIT_ECERTIFICATE when it fails the basic tests
Merge pull request #2683 from libgit2/cmn/remote-unify

remote: unify the creation code
Merge pull request #2661 from swisspol/2656

Changed context_lines and interhunk_lines to uint32_t to match struct s_xdemitconf
Add test script
Added Xcode script
Fixed active_refspecs field not initialized on new git_remote objects
Fixed git_remote_write_fetchhead() to handle tag refspecs
Fixed GIT_REMOTE_DOWNLOAD_TAGS_ALL to behave like git