Fix Linux error and warnings in Fem2DRep unit test
Fix cpplint warnings in Fem2DRep unit test
Improve documentation and fix spacing
Merge branch 'fix/fem2dBugs' into 'master'

Fix 2 bugs in Fem2D

+1: Walter Schoen, gsathyaseelan, Harald Scheirich

Merged-on: https://www.assembla.com/code/OpenSurgSim/git/merge_requests/814583
Merge branch 'master' of git.assembla.com:OpenSurgSim into feature/fem2DValidationTests