Add regex to standard library

[calebzulawski]

I think an implementation could look something like:

regex = std:String:regex "lib(?P<name>).so.[0-9]+"

match $library [
    $regex :captures -> std:log:info "matched ^(captures:name)"
    _ -> ...
]

[afranchuk]

I was hesitant to include regex due to size. But it'll be smaller than, say, the network stack, and that's already included in the standard library (mainly as a means to bootstrap more functionality over the network). It probably won't be that big an addition when all's said and done.