Improve the ngdoc comments generator.

Remove `@deprecated` from scope methods added by the generator.

Ensure the deprecation messages in original scope methods use upper-case
name of the model to make it clear the referred method should be invoked
on the constructor (statically), not on an instance.

Close #48
Fix ngdoc generated for scope methods

Create a dummy `lbServices.{model}.{scope}` object that groups all
nested methods except the top-level query.

Before this change, scope methods were mixed with regular model methods,
because ngdoc/docular does not support method names with a dot.
Hide original scope methods from ngdoc

Remove `prototype$__{op}_{scope}__` from ngdoc. These methods don't work
correctly and are included for backwards compatibility only.
Update dependencies

Most notably:
  express to 4.x
  loopback to 2.x
Merge pull request #57 from strongloop/feature/various-improvements

Various improvements