[5.5] Let In validation parameters contain commas

[balping]

Prevoiusly

Rule::in([
    'alpha,beta',
    'gamma,delta'
]);

was parsed to in:alpha,beta,gamma,delta meaning that 4 values would pass this rule instead of the quite explicitly stated 2 possibilities.

This PR fixes the above bug by enclosing the listed values by double quotes. This is understood by the function str_getcsv which is used later on.

Because of introducing extra double quotes, it is necessary to escape existing double quotes (with a double quote, resulting double-double quotes, silly CSV standard...) , this is also implemented here.

[devcircus]

Shouldn't the following work?
Rule::in([
'"alpha,beta",
"gamma,delta"'
]);

[balping]

The validator should match the exact strings listed in that array. A developer should be not required to have knowledge about the behind-the-scenes usage of str_getcsv or about how escaping in that function works. It took me ~30 minutes to find out both and I'd like to save that time for others.

I dont know what you mean by 'work', but in the example provided by you, the only value passing that rule is the string

'"alpha,beta",
"gamma,delta"'

If your concern are new line characters, they are handeled correctly, I added tests to prove that.