Aurelia binding 2 reference creates forks

[rockResolve]

aurelia-binding has a new major version, so to avoid jspm forks should change dependency to "aurelia-binding": "^1.0.0-rc.1.0.0 || ^2.0.0"

However jspm does allow semver ranges, so have to change dependency to "aurelia-binding": "2.0.0"

See https://github.com/aurelia/framework/pull/897