Fix some of the resolver.reject's to return Error objects

There are two more rejects that I did not dare touch, as they seemed to return some objects of unspecified form instead of strings. Namely:

Line 36 in [lib/ComponentFactory.js](lib/ComponentFactory.js)

and

Line 72 in [lib/lifecycle.js](lib/lifecycle.js)

There are also some uses of "sentinel" as a reject reason in [test/node/aop-test.js](test/node/aop-test.js) but since it's in the test it might not matter all that much.