rm unnecessary deepcopy

[stevengj]

The string-conversion routines made an unnecessary deepcopy of the result of unsafe_string, which is already documented to be a copy.

Also should be no need for the pointer call, since unsafe_string already has a Cstring method.

(The trimzeros function also does a lot of unnecessary copying, but fixing this is more work. Ideally you would do the trimming at the same time as copying from the Cstring pointer.)

[JeffreySarnoff]

thank you