Add config file and ability to select time and color axis.

[JostTim]

New convention is new lab is time as first dimention.
To keep this library compatible between labs and conventions, there is the need to be able to specify the default axis for time.
However, to allow for retrocompatibility too, this argument must be set by default to a value that is not the vallue of my current lab. To avoid annoyingly add this argument each time, i'll need to make a configfile in the style of matplotlib rcparams. As such, values in the configfile are taken by default if argument is not supplied, and if it is, the argument taken in specific functions takes priority over the one in the configfile.