Unified meaning and mutual relations of some inplace configurations.

Unified meaning and mutual relations of some inplace configurations.

This commit changes the behaviour of three groups of options:

    re2c:define:YYSETCONDITION
    re2c:define:YYSETCONDITION@cond
    re2c:define:YYSETCONDITION:naked

    re2c:define:YYSETSTATE
    re2c:define:YYSETSTATE@state
    re2c:define:YYSETSTATE:naked (added by this commit)

    re2c:define:YYFILL
    re2c:define:YYFILL@len
    re2c:yyfill:parameter
    re2c:define:YYFILL:naked

The changes should be backwards compatible (meaning that old code that
compiled should still compile), but it may add empty statements or statements
with no effect for some configurations, e.g.:
    YYSETCONDTITION(0);(0);
These changes were necessary to unify re2c behaviour, remove counter-intuitive
cases and make it possible to write comprehensible option descriptions.

In short, the changes are:
    - 'naked' triggers generation of argument-in-braces and semicolon;
    - 'parameter' triggers generation of argument-in-braces (when applicable,
      'naked' has priority over 'parameter');
    - argument templates ('@cond', '@state', '@len') don't force other
      configurations, they also don't influence on argument-in-braces;

Added test generator and autogenerated tests.