Merge pull request #8 from ajhager/dev

Merge in 0.5.0 from dev
Merge pull request #9 from ajhager/dev

Pull in some changes form 0.6.0
Merge pull request #10 from ajhager/dev

Fix onunload event for js
Update to use new webgl library
Updated build info in README
Merge from master
Change glfw backend to use webgl repo