Fix the problem where `registry.defaultDataSources` has two instances:
- `require('loopback').defaultDataSources` used by
`loopback.autoAttach()`
- `require('./registry').defaultDataSources` used by
`app.dataSource`.
I am intentionally leaving out unit-tests as the whole `autoAttach`
feature is going to be deleted before 2.0 is released.
Move isBrowser and isServer from lib/loopback to a new file lib/runtime.
Move all Model and DataSource related methods like `createModel` and
`createDataSource` to lib/registry.
Remove the circular dependency between lib/application and lib/loopback,
by loading lib/registry and/or lib/runtime instead of lib/loopback
where appropriate
This commit is only moving the code around, the functionality should
not be changed at all.
Miroslav Bajtoš