Finished with basic regex patterns
Finished with Parser-combinators.
Added PlusPattern for '+' regex operator
Special IgnoredParser to skip terminal symbols while building AST.
Also auxiliary methods expand/collapse for conversions
between parsers that return single value of specified type
and parsers that return list of such values
Fixed message in exception
Regex grammar
Changed formatting
Updated toString of Pattern classes
Saving internal Parser state wasn't a clever idea,
because of recursive rules.
Now all parsers internally return special Result object
containing both parse result and next token index.
Created static match method in Regex class
Removed debug output
Added support for '\n', '\t' in tokenizer.
Added tests. Fixed '\w' processing.