Changes for comparison plots

- The system can now re-color the edges when visualizing a plot comparison.
- The system can now select a master set of coordinates, this set of coordinates is where all the other coordinates originate.
- Scaling by the percent explained now works for vectors and edges in the case of a plot comparison.
- A bunch of typos have been removed from the comments.
- A bug was fixed where axes would always re-color back to white when the coordinates were scaled by the percents explained.
- A semantic bug was corrected where the checkbox to enable the edges visibility was negated.
- Biplots are now removed from the plot when they are hidden not turned to 0 in opacity.
- Axes are no longer transparent, which in part helps for #151.
- The script interface was modified to be aware of multiple procrustes comparisons as introduced in [qiime/qiime pull request 1020](https://github.com/qiime/qiime/pull/1020/files); the script interface will check for naming conventions.
- Elements in the view table have been re-ordered to be a little bit more consistent.
    
    Fixes #121, fixes #144 and fixes #143.