teach fudge to know about envvars

Now in addition to #?rakudo.moar lines, you can do three other things

    1) negate the line to #!rakudo.moar to fudge anything *except* rakudo.moar
    2) test #?FOO, if environment variable is set, perform action
    2) test #!FOO, if environment variable is *not* set, perform action

We're using this temporary to mark #!LOLLY tests.