added off-target filter profiles based on distribution of off-target counts
added thumbnail links to example output of crispr pair search
added OT distribution graphs to help. Moved distribution stats to module
example thumbnails added to main page. crispr help text and images updated
Merge branch 'devel' into filter_crisprs
Merge branch 'devel'
v0.022

   Added off-target count distribution graphs and filters