Remove whitespace from ends of lines
Smarten up `fromNodeCallback` (see description)

Passing values from other streams into `fromCallback` and
`fromNodeCallback` is pretty cumbersome. This patch hacks
`fromNodeCallback` so that it can take any number of primitive values
and `Observable`s (`EventStream` and `Property` objects, for instance).
It will call its callback once it has all the values from all the
sources.
Simplify, also wrap `fromCallback`
Further simplify. Gotta find a better name for the wrapper.
Remove ugly hack. Still need good name.
Rename to lift; add and refactor test cases
Remove whitespace from ends of lines in README
Add result of `lift` to README
Rename to liftCallback, clarify README
Simplify testLiftedCallback
Merge pull request #143 from abesto/smart-from-callback

Better partial support for `from(Node)Callback` (pull request). Close #133.