[WIP] Imported logical NOT rule from "doctrine/doctrine2"

[phansys]

Q	A
Bug fix?	no
New feature?	no
BC breaks?	no
Deprecations?	no
Tests pass?	yes
Fixed tickets
License	MIT
Doc PR

TODO:

• Add PHP CodeSniffer rule
• Add tests

[deeky666]

@doctrine/team-doctrine2 I guess with this PR it's about time to decide whether we enforce a leading space or leave it for PSR-2 compat.

[phansys]

@deeky666, @Ocramius; is this library used anywhere? Almost one year ago I've opened doctrine/orm#1470, getting this feedback:

Can't add it to the build atm: would need to first fix most issues

Now, checking the status of these PRs again, I found that the unit tests don't work due an issue with PHP_CodeSniffer:

PHP Fatal error: 'continue' not in the 'loop' or 'switch' context.

Here we have a constraint for the 1.x branch (my resolved version is 1.5.2), which seems to be not maintained anymore: squizlabs/PHP_CodeSniffer#1046. I looked at whole 1.x versions of the dependency, and this bug is present in all of them, so narrowing the constraint to a more restrictive version is also not the solution.
While I'm trying to help, it's hard to do in this way. I've made a new phpunit run after updating the squizlabs/php_codesniffer constraint to ^2.0, but all the tests are failing, I assume that there are some changes between these versions which aren't backguard compatible:

FAILURES!
Tests: 203, Assertions: 0, Failures: 200, Skipped: 3.

Please, note that I haven't experience with PHP_CodeSniffer, so any hint is very appreciated.

[Ocramius]

Totally missed this. Indeed, the project won't run with 2.x, but should... Can't help further myself tho: I know as much as you do about PHP_CodeSniffer...

[sovaalexandr]

@doctrine/team-doctrine2 any progress on #7 (comment) ? Now I'm getting violation when try to

Add spaces around a negation if condition if ( ! $cond)

[lcobucci]

Sniffs implemented on #8 (along with PHPCS v3 compatibility).