Add CONTINUE and BREAK operators

* remove $math in "case T_ECHO:"
* add function getNextToken
* add $ifOperators
* add operators &&, ||
* fix pass-by-reference

Time: 276 ms, Memory: 21.25Mb
OK (276 tests, 278 assertions)

Change-Id: I0a529031c6ac33d56d9f44621be79a9fb9a87bb2