This create a new git_iterator type of object that provides a
uniform interface for iterating over the index, an arbitrary
tree, or the working directory of a repository.
As part of this, git ignore support was extended to support
push and pop of directory-based ignore files as the working
directory is being traversed (so the array of ignores does
not have to be recreated at each directory during traveral).
There are a number of other small utility functions in buffer,
path, vector, and fileops that are included in this patch
that made the iterator implementation cleaner.
Add unit tests to confirm ignore directory pattern matches and
to confirm that ignore and attribute files are loaded properly
into the attribute file cache.
Per issue #533, the handling of relative paths in attribute
and ignore files was not right. Fixed this by pre-joining
the relative path of the attribute/ignore file onto the match
string when a full path match is required.
Unfortunately, fixing this required a bit more code than I
would have liked because I had to juggle things around so that
the fnmatch parser would have sufficient information to prepend
the relative path when it was needed.
Adds support for .gitignore files to git_status_foreach() and
git_status_file(). This includes refactoring the gitattributes
code to share logic where possible. The GIT_STATUS_IGNORED flag
will now be passed in for files that are ignored (provided they
are not already in the index or the head of repo).
