Added new BandMAtrix
Added new ShiftMatrix
First operators moved over
Fix constructor
fixed multiply
take slice of operator
Added addentries! for TimesOperator
Allow constant rhs
Mutable almost banded
MutableAlmost...->Almost...
\ works!
fixed error in *
Fourier Operators
BandedMatrix*Vector
Removed some more ::ShiftArray
FFun tests pass
Work on mult
Transpose and null
PDE Setup
Fast addentries! for ShiftMatrix
Fixed ultraspherical multiplication