allow coefficients to be any number.

type of number can be inferred from Domain
Merge pull request #86 from goretkin/general_number

WIP: generic number type2
add tests
Merge pull request #100 from goretkin/general_number

add tests
Merge pull request #103 from ApproxFun/fix-band-matrix

Fix band matrix for addentries!
Merge pull request #104 from ApproxFun/master

sync master