* Add ECR entry from language-crystal
* Add HTML+ECR to Languages.
* Create greeting.erb sample
From the ECR documentation: http://crystal-lang.org/api/ECR.html
* Rename greeting.erb to greeting.ecr
* Rename samples/HTML-ERB/greeting.ecr to samples/HTML-ECR/greeting.ecr
* Update Crystal submodule.
This contains the ECR highlighting.
* Proper named HTML+ECR folder.
The GitHub website just wouldn't do the folder right.
* Add .ecr file extension to ECR
