Allow Consts with PascalCase

[sunkan]

I think we should relax the limitation we have on constant naming to allow both UPPERCASE and PascalCase

[dcolt]

I'm a little bit torn on this one.
The reason being: I've learned that const properties "should" be UPPERCASE or even SCREAMING_SNAKE_CASE, so it's easy to distinguish from a regular variable.

However this doesn't hold true in the same sense for PHP, as we always need to scope it to the class it's from anyway, including self::, and if it's a variable it has to be prefixed with the $...

So from the point of view that it just "feels wrong" that is should allow PascalCase, I don't really have an objection to it other than perhaps the consistency in the code base.

Could you give some case where you think it would be better to use the PascalCase instead of UPPERCASE or even SCREAMING_SNAKE_CASE?