Added CeO2 as a calibrant, updated Ag Behenate, Si and Cr2O3 values
Made reciprocal cell subclass unit cell, added overridden setters in
unit cell to update lengths and angles, and added unit tests
Added TODO to refactor HKL class as it is really a d-spacing class
Added a getter of wavelength to q-space
Added setter of geometry of a detector and tweaked javadoc for tilt
angle getter