added text to address #22

this should fix the "add explanatory text for this new visualization" piece of #22.
fixed typo
fixed typo - thanks @ElDeveloper!
Merge pull request #92 from gregcaporaso/issue-22

added text on two PCoA plots
Change HTML links to open a new tab

All of the visualizations linked in the description for each type of
data visualization will open a new tab, instead of changing the current
context.

References to other resources, like the UniFrac paper, Greengenes etc,
were also changed to have the same behaviour.

Test module for format is updated to reflect these changes.

This should fix issue #91
Merge pull request #95 from ElDeveloper/issue_91

Change HTML links to open a new tab
Merge branch 'master' into issue-70

Conflicts:
	my_microbes/format.py
several fixes to text

 - some clarity issues (thanks @jrrideout!)
 - made email address a mailto link
 - added link to NAU144 data