More linter-suggested formatting changes, warnings added for non-intersection,...

More linter-suggested formatting changes, warnings added for non-intersection, and clean up duplicate code (#311)

* More cpplint suggested changes

* call computeallsensorpartials from parent

* Added warning for when imageToGround doesn't intersect target

* More cpplint-suggested changes

* Add README.md explaining that we use a pared-down version of the Google Style Guide