Turn the parsed signature into an object

[schwern]

Similar to #30, turn the signature as a whole into an object.

The next step after this is likely to make a Method::Signatures object and hang the signature object off that... or just meld them together.

[schwern]

One benefit would be to separate signature parsing from the rest of the Devel::Declare stuff like so:

my $sig = Method::Signatures->new(q[($foo, $bar = 42)]);

This would allow someone to do interesting things with just the signature parsing but doing whatever they like for the grammar.

Also @rafl and others have pointed out that signatures are really just an array unpacking language. This would allow that use.

[schwern]

This is largely done with Method::Signatures::Signature. MS::Signature is all about parsing the signature syntax into a data object. MS handles turning that into code and injecting it.

I'm going to call it done, even though it's not externally documented, as that will come when we need it.

[barefootcoder]

Hunh. I meant to close this one when I merged thne pull request. My bad.