Revert "Update php-font-lib requirement" - It breaks composer

This reverts commit ffb51908cb6036a096b25c96a3f65dd30144f893.

If your lib requires dev-master, composer can't resolve it without setting the min stability of my project to dev, which I don't want to do on production. The default min-stability of composer is stable, so this causes trouble.

	jdonat > JesseDonat-MBP ~CIL ±2.0.6⚡ » composer update                                                                  2↵ 16:42:49
	Loading composer repositories with package information
	Updating dependencies (including require-dev)                 
	Your requirements could not be resolved to an installable set of packages.
	
	  Problem 1
	    - dompdf/dompdf dev-master requires phenx/php-font-lib dev-master -> no matching package found.
	    - dompdf/dompdf dev-master requires phenx/php-font-lib dev-master -> no matching package found.
	    - Installation request for dompdf/dompdf dev-master -> satisfiable by dompdf/dompdf[dev-master].
	
	Potential causes:
	 - A typo in the package name
	 - The package is not available in a stable-enough version according to your minimum-stability setting
	   see <https://groups.google.com/d/topic/composer-dev/_g3ASeIFlrc/discussion> for more details.
	
	Read <http://getcomposer.org/doc/articles/troubleshooting.md> for further common problems.