Create a strategy for the indentation level to use in parsers

[skiwi2]

Currently you can create parsers with the following idiom:

• CreateGameEntryParser.create(), will match entries at any indentation level.
• CreateGameEntryParser.createForIndentation(indentation), will match entries at the specific indentation level.

It would be better to supply some kind of strategy that allows it to match indentation levels either smaller than, equal or bigger than a specified indentation level. This should be able to be combined with a strategy that increases the specified indentation level by for example 4.