reduce the number of errors in http access about swarm HOT 2 CLOSED

@homotopycolimit great stuff, are you gonna tackle the fixes?

from swarm.

The configuration file should be populated with default values or should be edited manually.. currently empty entries in the config file are overwritten by any command line arguments. This leads to funky config files if the first time you run swarm you get an argument wrong. For example if I change httpaddr to '' in my config and then run swarm with --httpaddr doofus, then I'll have doofus stuck in my config until I change it manually.

This should be solved by ethereum/go-ethereum#15548
The other points are covered by these issues:
#153
#154
#155
#156
#158
#162

from swarm.