Correct copyright lines in grammar classes
Implement transiting expressions, add a punctuation character

Implement transiting expressions to place an expression with the alternative
grammar in the standard grammar context, and vice versa.
Make '#' a punctuation (reserved) character in both the standard and
alternative grammar.
Fix the primary expression rule in the alternative grammar, allow whitespaces.
Add vector expressions and fix colon infixes in the alternative grammar

Add vector expression rule in the alternative grammar.
Fix a bug of the colon infix rule in the alternative grammar.
Add YacqServices.DefaultReader property

Add DefaultReader static property in YacqServices class to be able to select
default reader (and grammar).