Update tests

[MKLau]

Remove tests for all features no longer supported.

[MKLau]

See Issue #61 Testing graph correctness

And from tfjmp Issue #53

"There should be test done to verify the good "connectivity" of the graph. There is people working on provenance evaluation in the community, maybe something useful will come out of it.

However, given known script, verifying that outputs connect to expected output through data derivation edges should be the minimum. Matt to find some scripts that are working and failing with the current version."

[MKLau]

http://testthat.r-lib.org