Disable xdebug.scream while lexing
Merge branch '0.9'
Add note about prettyPrintFile() to docs
Update constant scalar expression support
Add experimental php-parse script

Script supporting dumping, pretty printing, serializing and resolving
names. Intended to help exploring and debugging the node tree.
Separate parser code from generated data
Use normal properties instead of static ones
Make names in the parser more descriptive

And improve the code a tad bit in general.

I left YY2TBLSTATES and YYNLSTATES around, because I don't fully
understand their role in the action double indexing.
Make sure that pretty printer preserves whitespace after <?php