Feature/replace regex

[nastymorbol]

Replaced some Regex with constant expressions for performance improvement.

[s-michael-telford]

I considered making similar changes, but was going to recommend using the built it char static functions instead. Specifically, char.IsAsciiDigit or char.IsDigit, char.IsAsciiLetter or char.IsLetter etc.

[nastymorbol]

Since the static char functions are unicode, i prefer to work with explicit ASCII characters. Unfortunately, I already had problems where my customers used some unicode characters using copy paste, which I then misinterpreted.