Add some tensor integrals
Intermediate results for NLO-D-gg
NLO-C function
Add more tests for graphs C and E
Update NLO-D.nb
Bugfix: NLO-D-gg is not reproducible

  Credit for fixing this bug goes to A.Kusina
Some cleaning
Add comments from A.Kusina
Add some tests
Merge branch 'integrate'
Bugfix: unclosed comment
Fix NLO tests