In python 3, subprocess uses bytes for input and output if
universal_newlines=False (the default). It uses str for input and
output if universal_newlines=True.
Since we mostly deal with strings, add universal_newlines=True to
subprocess.check_output.
For a long time, rest_dispatch has had this hack where we have to
create a copy of it in each views file using it, in order to directly
access the globals list in that file. This removes that hack, instead
making rest_dispatch just use Django's import_string to access the
target method to use.
[tweaked and reorganized from acrefoot's original branch in various
ways by tabbott]