Change CSS output to compressed
Disable line comments in CSS output
Move MP profile CSS into a partial to make maintenance easier
Convert existing topics to new rendering system.
Remove stray end-of-line spaces in httpd.conf
New Member class with single isDead() function
New PolicyPositions class to interact with members' policy positions.

Code mostly taken from existing MP profile page.
Introduce new single topic controller.
Add list of MP positions to topic page.

Also moves topic data from distinct files into the top of the topic
controller.
Migrate MP profile pages to use new PolicyPositions class.

Closes #475
Upgrade PHPUnit to 4.0, update Composer and site dependencies.
Tidy Sass into partials to allow easier maintenance, Sass improvements

* New mySociety header bar Sass moved to existing partial.
* Site header and footer Sass moved into partials.
* Existing policies Sass moved into partial.
* New topics Sass added.
* Tidied duplicate and un-nested Sass to clarify intent.
Implement function on new Member class to get image URL.
Implement redesign of topic pages using new layout.