Adds some string and int extension methods

[tristonplummer]

What has been done?

String.prefixAn()

Usage:

val name = "adamantite bar".prefixAn() // an adamantite bar
val name = "runite bar".prefixAn() // a runite bar

Int.toLiteral()

val literal = 73.toLiteral() // seventy-three
val literal = 22.toLiteral() // twenty-two