Merge pull request #14 from mjohnson541/master

New plotting functions and notebooks
Merge pull request #15 from mjohnson541/master

Function naming conventions created
Merge pull request #16 from mjohnson541/master

Function tweaking and new plot tests
Merge pull request #17 from mjohnson541/master

potential pressure height conversion functions
Added test for IWC
Merge pull request #18 from scollis/master

Added test for IWC
Merge pull request #4 from EVS-ATMOS/master

remerging