Factor out a get_param_addr function.
Factor out a get_param_addr function.

This gets an address spec from a movie parameter, parses it and returns
the address.

infinity0/flashproxy,infinity0/flashproxy,infinity0/flashproxy,glamrock/flashproxy,arlolra/flashproxy,glamrock/flashproxy,glamrock/flashproxy,arlolra/flashproxy,arlolra/flashproxy,glamrock/flashproxy,infinity0/flashproxy,arlolra/flashproxy,glamrock/flashproxy,infinity0/flashproxy,arlolra/flashproxy,infinity0/flashproxy,arlolra/flashproxy,arlolra/flashproxy,glamrock/flashproxy