Add migration to capture new help text on 1000g and EVS concepts

This new text is meant to clear up any confusion when entering
percentages in the range controls. The percentages should be entered as
values in the range [0.0, 1.0] but this was not clear before. This is
now spelled out in the help text with an example.

Signed-off-by: Don Naegely <naegelyd@gmail.com>
Merge pull request #167 from cbmi/issue-103

Add migration to capture new help text on 1000g and EVS concepts