Add details-for-tree-entry

This adds an example which shows how to retrieve details for a
tree entry. You have to go into the index and get the details
since they aren't stored on the tree entry itself. This is the same
for a blob entry as well.

This helps with #221
Merge pull request #285 from nodegit/details-for-tree-entry

Add details-for-tree-entry
Added editor config
Added tests for commit

 - messageRaw
 - messageEncoding
 - summary
 - owner
 - parentcount
Merge pull request #290 from nkt/tests/commit

Added tests for commit
Merge pull request #289 from nkt/editorconfig

Added editor config
Increased support for Push, Remote and Direction enums
Added a push example
Merge pull request #288 from nodegit/push-example

Added Push example
get a merge example up and running!
clean up and comment merge example
Changed merge so that you don't have to pass null in for options
merge with conflicts example partly done
merge examples now work!
merge tests!