And implement the option init functions for this and the format options.

This makes us be closer to git's tests, and lets us better describe what
we expect from the output.

When we describe the workdir, we perform a describe on HEAD and then
check to see if the worktree is dirty. If it is and we have a suffix
string, we append that to the buffer.

Instead of printing out to the buffer inside the information-gathering
phase, write the data to a intermediate result structure.

This allows us to split the options into gathering options and
formatting options, simplifying the gathering code.

We don't describe arbitrary object, so let's give it the name of the one
object type we accept.

Stash ignored directories

Pool/Index data is not aligned

Correctly handle getaddrinfo return result

global: free the error message when exiting a thread

* Ensure alignment by copying the content into a structure on the stack

Remove unused buf variable from path/core test.

The getaddrinfo function indicates failure with a non-zero return code,
but this code is not necessarily negative. On platforms like Android
where the code is positive, a failed call causes libgit2 to segfault.

Factor 40 and 41 constants from source.

It looks like what Travis wants is a list of hashes, rather than a hash
with a list.

Fix `git_path_walk_up` to work with non-rooted paths

Replace void casts with GIT_UNUSED.

Provide a callback for certificate validation

travis: run valgrind only once