Resolve #355, fix snake_case_methods and provide a test
Rootpy-ized F1,F2,F3, which are Plottable
Merge pull request #356 from pwaller/rootpy-func

Rootpy-ized F1,F2,F3, which are Plottable
Merge pull request #355 from pwaller/issue-355

`snake_case_methods` breaks descriptors