Ability to not log every request, optimizations, db_index, and a management command

[JoshData]

Hope this is helpful.

• adds a setting to not log every request, which makes this easier to use on a high-load site
• use Python's cProfile class to profile all method calls in a request (with a setting to turn it on)
• adds a management command to clear the request/response/etc. tables

and

• doesn't compute a reverse or load the configuration on every request
• adds some indexes to the models
• tweaks templates, README
• on the SQL queries page, display the query start time as relative to the request start time

[mtford90]

This looks awesome Josh, cheers - limiting num. requests intercepted is a great shout and really like the idea of integrating cProfile.

I'll merge this all in tommorow and will fix the broken build - think it's the usual python 2/3 stuff (iteritems etc).

[JoshData]

Fantastic.

Thanks for getting this project going!

[mtford90]

My pleasure =).

Just merged this in and released to PyPi as 0.4. I took the liberty of making a few style changes to the cProfile stuff - just added scrolling for overflow and made Silk's own profiling section more explicit. The build fail was simply down to StringIO being moved into the io module in py >3 so no issues there

Thanks again!