[Asserts] Unification of assertAttribute:andKey: method

`assertAttributeType:` and `assertAttributeKey:`
unified in:
`assertAttributeType:andKey:`

Signed-off-by: Miguel M. Almeida <miguelcma@gmail.com>
[Asserts] Asserts now produce a warning, if in production

* A new Log level was introduced: `kLQLogLevelAssert` (default for production)
* `LQLog()` now outputs in production too

Signed-off-by: Miguel M. Almeida <miguelcma@gmail.com>
Merge branch 'asserts' into development