Fix 2D User Defined Plots (issue #13)

[bcaddy]

Summary

It appears that the issue was the usage of the bitwise not operator (~) in a handful of places where logical not operator (not) should have been used. In addition to the user-defined plots issue this might clear up some other issues or odd behavior in other places that were affected by this issue.

closes #13

Instructions for Getting This Branch

$ git clone git@github.com:bcaddy/Iseult.git bobs-iseult
$ cd bobs-iseult
$ git checkout --track origin/master-iss13

[bcaddy]

@pcrumley, these are the changes I was talking about

[ntoles]

Vassilis confirmed that the bug is gone! Thank you!