Support for index-entries
Add a few missing config setters and getters
Add a few more missing config functions
Add iterators and ConfigEntry
Lock the thread so we can get the error message
Merge pull request #42 from libgit2/cmn/config

Wrap some more config functions
Remove pointer to git_index_entry

We have all the data
Adjust to oid -> id
Merge branch 'index-entries'
Remove 'oid' as id name

Following the cleanup from libgit2, let's not use 'oid' unless we mean
the name of the data type. In the other cases, we mean an identifier,
hence the name 'id'.
Added git error code to the error object.
Convert the rest of the errors
Merge branch 'more-errors'
Add thread locking
Merge branch 'master' of https://github.com/libgit2/git2go into add-branch-lookup
LastError -> MakeGitError