Overridable default configuration via config file

[kazamatzuri]

We need the ability to have a customizable default configuration for things like

• default graph size
• default colors

[kazamatzuri]

would also be useful for the fileprefix stuff

[kazamatzuri]

61b1fe832 is taking a step in the right direction. now we just have to add a config file to let people set those outside of command line parameters

[kazamatzuri]

72e0194 is giving us config file parsing and implements an example option (figure size, due to popular demand)