Support all 1.x versions of datasource-juggler

Modify the loopback-datasource-juggler semver specifier in
peerDependencies and devDependencies from "~1.3.11" to "^1.3.11".
The goal is to support newer 1.x versions like 1.4.0 or 1.5.x.
Merge pull request #258 from strongloop/feature/relax-juggler-dependency

Support all 1.x versions of datasource-juggler