Created a class to generate SupportFlow thread statistics
Created a page to statistics

Currently it shows new/open/closed tickets stats for different time period
as well as different tags
Clicking the number of matching tickets will show them in `All threads`
page
Added type to style tag to maintain backward compatibiliy with old browsers
Add comments to code in statistics page
Merge pull request #136 from VarunAgw/stats

Add a Statistics screen.
Autosaving thread data

It will autosave all the elements with class `sf_autosave` as post meta
with key `_sf_autosave_$element_id`. Currenly it autosave cc, bcc and reply box.

Currently it don't support autosave functionality in new threads
Sending element ID rather than name during autosave
Corrected WP coding standard
Auto save also new threads
Enable autosave for post title and respondents in draft thread only