Create shortcuts for ASCII inputs

[behnam]

A big part of the input to many Unicode algorithms is ASCII-only or ASCII-majority, specially in early stages of application development.

Most properties/algorithms have a clear and easy effect on ASCII input, that can be put together in a couple of lines of code, usually. And in many cases, this only adds one if condition to the log(n) bsearch checks that follows.

We want to benefit from this and make these algorithms much faster for the common case, to make adoption easier for developers.