[2.5] CS Fixes And Removed Unused Imports

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | N/A
| License       | MIT
| Doc PR        | N/A

##### This pull request fixes some cs issues in symfony 2.5.

I've applied the same set of fixes that I did to the 2.3 branch.

There are far fewer fixes than there were for 2.3, so I've just done them all at once.
I think `@return` usually is above `@throws`.