Generate Tuples, Functions, MetaGrammar & according tests

[danieldietrich]

See also #12.

Write a generator that is compiled and run in the Maven generate-sources phase.

The classes Tuples and Functions (+ tests) mentioned above are highly repetitive and an ideal target for code generation.

To take advantage of grammar evolution and continuous grammar bootstrapping (as described in #33) execute the grammar bootstrapping as part of the generate-sources phase (does this make sende?).

Tasks:

Create generator framework:

• create generator templates (simulate java rich-string by denoting as array of strings which is joined with newline!?)
• write magic string indentation function for java like this: https://gist.github.com/danieldietrich/5174348

Update Maven .pom:

• compile generator
• run generator
• add new source directories, e.g. src/main/gen, src/test/gen