Updated Documentation pages about switch-case expressions

Changed colon in syntax after case keyword to “then” keyword, and also made it optional. End the case portion by a new line or the “then” keyword. Also updated PDF export of the pages.
Added experimental PHP parser of Coral source files

The parser includes a silly test program and a simple use of Coral\Tokenizer to tokenize a file and print it formatted in HTML. Upcoming versions will contain a form for user uploaded Coral sources, which won’t be stored, only parsed and outputted.