Provide enough space for axis labels by default

[seifertm]

When creating a new plot, axis labels are cut off and the user has to set the plot insets manually. Instead, there should be enough space for axis labels in the default configuration.

Imported from trac ticket #63, created by mseifert on 12-04-2013 at 12:01, last modified: 01-24-2014 at 14:13