Inconsistent syntax for GT and TGG syntax

[patrickrobrecht]

• The TGG syntax prefixes keywords with an # (e. g. #import, #rule), while GT does not do that (import, rule, ...).
• Attribute conditions within a node are prefixed with (.) to automatically enable Xtext auto-completion. This is not necessary for TGGs.
• The GT formatter forces exactly one space between a keyword and the following word, e. g.

register: FamilyRegister {
		++ -families -> family
}

The TGG does not add spaces (e. g. ++ac:AlgorithmContainer).

• TGG uses #extends for rule refinement instead of refines used in the GT syntax.

[anthonyanjorin]

GT uses „refines“ while TGG uses „#extends“.