CS fixer, PSR2.

[birkett]

This commit is the result of running cs-fixer / CodeSniffer over the code. This is close to PSR1 + PSR2 compliant - the remaining issues are:

• Files are defining classes / methods, and running code with effects. They should do one or the other, not both.
• Some very long lines of code.

These will be fixed with refactoring, to follow.

Breaking changes: none Functionality changes: none

I recommend a quick test of all functionality before merging this, just in case something changed.

Linking to #57