Add possibility to set custom separator

[matrixik]

[matrixik]

Not sure if I want to add this functionality. I saw some forks that have basically only one additional commit with changing separator.

Pros:

• well, ability to set custom separator

Cons:

• another global variable (too late to break people code)
• IsSlug is probably slower
• bug with regexp: compilation is happening too early so separator for it is always -

[matrixik]

Will leave it open for now, maybe someone have some feedback.

[matrixik]

Shit, one more bug now with defaultSubs initialized with init...