check for @graph keyword in manifest

See https://github.com/UniversalViewer/universalviewer/issues/385

Interesting... would it be possible to add your manifest as a test fixture with accompanying test?
https://github.com/viewdir/manifesto/tree/master/test/fixtures
Maybe just testing that it loads correctly. This would also ensure it doesn't break any other tests.

@edsilv thank you for the reply.  I added a test that checks if it loads correctly, and that resources can be read (I reused getManifestType() and getSequenceByIndex(0) ).  See lines 117-124 in this file.
@graph_test.txt
All other tests still pass with the change.


Fix custom lfs

Fix support of external git lfs repository by checking out file .lfsconfig before running git lfs fetch.

 Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.:x: tmisch sign nowYou have signed the CLA already but the status is still pending? Let us recheck it.

@tmisch - I have not forgotten about this. We needed to get a few other things in and I have not had time to circle back to this. I had made an attempt to get rid of the duplicate classes that perform git functions to make this update a little easier, but that effort has also stalled for me.

@jtpetty - Thanks for letting me know what's going on. I thought that the PR was stuck because of the unit test failure that is fixed meanwhile.

Tested locally - LGTM, thanks!

@anatolybolshakov and you for taking over. good luck