Add BaseReflectivity class

New class that parses information out of a Base Reflectivity product
file.
Add getFloatColorValues() method, clean up code

Adds method that returns the color values as float values, rather than
ints.

Other changes that make the code more readable.
Add Unsigned class

New class that handles storing/accessing bytes to maintain their
unsigned-ness.  Useful for minimizing memory usage.