Enhancements 2 - with cs

[Chris Muller]

> The only note worthrthy change is ByteString>>alphabeticalNext. It is
> essential for read:from:upTo: as we have previously discussed.

If you don't mind, I decided against incorporating this implementation.  It
would not find "tazmania" when searching for "taz".  The solution I want to use
is

  ^ (self asByteArray asInteger + 1) asByteArray asString

but it requires ByteArray>>#asInteger extension offered by Cryptography.  Now,
Cryptography will be a required prereq for Magma real-soon now anyway.  In the
meantime, I hope you won't mind making #alphabeticalNext part of the demo
package.

 - Chris