Use X-Forwarded-For and X-Forwarded-Proto headers, instead of X-Real-IP and X-Scheme

Add healthcheck UA to inform server about identity

test fix

Adding "healthcheck.io" as User-Agent to inform webhook handler server about request is specific from healthcheck.

remove channel should always redirect even if removal fails

defer inserting the password field into the dom

dont include tests in coverage calculation

use basetestcase for most test cases that require predefined user

fix docs page crashing if welcome code is expired

fix tests and optimize authentication and fix some unclosed markup

Otherwise, if period=1m and grace=1m then we can end up generating huge useless tables.

Check.n_pings now stores the total number of pings the check has ever received. Running "prunepings" command doesn't affect this field. +a new "prunepingsslow" command which works in smaller chunks so is appropriate for initial pruning of a huge api_ping table.

Update README.md to reflect that django1.9 is used