Added altitude to coordConv.
Tests updated to include altitude.
Changed output type to correspond to input type.
Made output type same as input type (float->float, list->list).
Minor format typo.
Improved output type == input type stuff so it actually works.
Changed a comment.
Merge branch 'develop' of github.com:vtsuperdarn/davitpy into feature-coordConv-altitude
Added comment about 32-bit system.
Merge branch 'develop' of github.com:vtsuperdarn/davitpy into feature-coordConv-altitude
Merge pull request #69 from vtsuperdarn/feature-coordConv-altitude

Adding altitude argument to coordConv