updated litus/php-cs to new HEAD
added a pre-commit git hook script

It does the following:
- check whether all filenames are ASCII
- run all changed files through php -l
- run all changed files through php-cs-fixer
- run all changed files through php -l again to make sure php-cs-fixer didn't break anything
- check whether there are whitespace issues
Ran php-cs-fixer with the new config