Enhancement: Include $lower attribute for dashed

[shatterproof]

By including $lower in the attributes for dashed it allows for the use cases of generating gift card codes or serial numbers (generally uppercase only) in a more efficient way than using strtoupper afterward.

[shatterproof]

Looked into the random failed test and addressed here: #17

[valorin]

Nice, I really like this!

Would an option to support upper be useful here as well? I guess you can apply upper on the output, but having it as part of it could be nice.

[shatterproof]

Currently when $lower is set to true for dashed (the default) both lowercase and uppercase will be used, when it is set to false only uppercase will be used. My goal here was to keep the attribute name consistent with other methods, but thinking about it again this might not be fully clear since one might think $lower as true means lowercase only.

What would you think about renaming this attribute only on dashed to $mixedCase instead of $lower for added clarity? Then when $mixedCase is true both uppercase and lowercase are used, when false only uppercase is used.

Alternatively if keeping the $lower naming consistent is desired, a comment could be added to this method's attribute to explain its behavior.

[valorin]

Ah good point, I misunderstood what it did, so the naming of $lower clearly doesn't work.

I like the idea of using $mixedCase instead - it's clearer what's going on.