manpage `install.sh` step incorrectly assumes self.prefix is set

[dnwe]

The setup.py seems to expect self.prefix (and self.root) to never be None. However, this fails on a --user or --home install.

e.g.,

$ pip3 install --upgrade --egg --user https://github.com/simon-r/dr14_t.meter/archive/master.zip
...
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/tmp/pip-jze75d24-build/setup.py", line 70, in <module>
    cmdclass={"install": dr14_install }
  File "/usr/lib/python3.4/distutils/core.py", line 148, in setup
    dist.run_commands()
  File "/usr/lib/python3.4/distutils/dist.py", line 955, in run_commands
    self.run_command(cmd)
  File "/usr/lib/python3.4/distutils/dist.py", line 974, in run_command
    cmd_obj.run()
  File "/tmp/pip-jze75d24-build/setup.py", line 42, in run
    prefix = re.sub( r'^/' , '' , self.prefix )
  File "/usr/lib/python3.4/re.py", line 179, in sub
    return _compile(pattern, flags).sub(repl, string, count)
TypeError: expected string or buffer

I think you should just be using self.install_data as the prefix under which to put the man files.