Introduce two modes: Scanner OR Search and Replace.

This is in preparation to introduce "saved" named regex values for later reference.
Add NamedGroupCount & NamedGroupPlaceholderCount fields and tests
Add a memory to named regex expressions with ${name} to recall memory

e.g. (?<name>[a-z]+)  remembers matched expression in the to pattern in the name variable.
To recall the value use ${name} in the to pattern.
Allow force printing of held regex named values when there is no from pattern

e.g. ~${name} will print the value of name without the need of a replacement string
Introduce Pickup term to represent Named Regex variables

Use term Pickup for the name of the named regex variable and PickupPlaceholder for the value of the Pickup. PickupPlaceholder syntax is $(pickup-name}
Add pickup test to stdio regression suite
fix ApplyReplacementFirst method to allow "~${pickup}" syntax & add tests
Major rewrite of README.MD. Releasing as v0.7