Updated Documentation pages

Syntax of loop structures updated: deprecated loop-while and loop-until in favor of a different approach.
CoralVM-PHP: Updated available lexical contexts
CoralVM-PHP: Added a few missing keywords
CoralVM-PHP: Added a few missing operators
CoralVM-PHP: Updated testing coral source
CoralVM-PHP: Updated rendered view of WhitespaceToken and added a utility method for future compiler
CoralVM-PHP: Updated Tokenizer to comply with the latest language changes and implemented some more lexical contexts