String refactoring, alpha updated

[Lendvai Attila]

Hi!

In main: String was cut into String and ASCIIString. It doesn't mean too
many api changes, currently String new will return ASCIIStrings as
before and probably this api will remain so when the i18n package is
fully integrated except it will return a smarter string implementation.
An important change is that Character is now accessible trough its
appropiate String prototypes; e.g. ASCIICharacter became ASCIIString
Character.

Hopefully I didn't break anything, but if something fails drop a mail to
the list.

- 101