+openjpeg

[mxcl]

Closes #223

[what-the-diff]

• Added a new package.yml file for openjpeg
• The url of the distributable is https://github.com/uclouvain/openjpeg/archive/v2.5.0.tar,gz and it has one component to be stripped off when unpacking
• Versions are fetched from github tags using uclouvain as owner and openjpeg as repository name