Various fixes & cleanup of some unused statements:
- 1 parse error in JsonBody.php
- several doc comment fixes
- missing break
- $this->open => $this->isOpen
- some class constants were accessed without self:: prefix
- wrong escaping of \ (backslash)
- if ($this->body) => if ($this->body != "") for allowing "0" as value
Align use statements...
Fix getBody comparison: now against != ""