Transform

closes #67 and closes #66.  Adds transformations of the CCDData object although uncertainties may not be handled correctly.  It also handles rebinning of ccddata objects. 
Yup, that's why I didn't include it.  Rebinning to smaller values ends up losing information.  I'd be tempted to add something that rebin only worked for larger sizes as the smaller sizes the result might be unpredictable.