`cutord` not working as advertised in the README.md file.

Using the test `test/spin1/a.jl` which defines the `DAMap` `a_fpp`, `cutord` gives the error:
```
julia> include("test/spin1/a.jl");

julia> cutord(a_fpp, 2)
ERROR: MethodError: no method matching cutord(::DAMap{StaticArraysCore.MVector{…}, StaticArraysCore.MVector{…}, Quaternion{…}, Nothing}, ::Int64)
The function `cutord` exists, but no method is defined for this combination of argument types.

Closest candidates are:
cutord(::TPS, ::Integer)
@ GTPSA ~/.julia/packages/GTPSA/rjfML/src/methods.jl:359

Stacktrace:
[1] top-level scope
@ REPL[48]:1
Some type information was truncated. Use `show(err)` to see complete types.
```