Inspector improvements

[skalarproduktraum]

This PR improves the inspector in the following ways:

• the font size is changed to 90% the regular font size to accommodate more controls in the inspector
• the MigLayout managers for all the inspector's constituents are changed to decrease white space in the inspector and make things more compact
• the transfer function editor for volumes now correctly shows up under the Volume group and transforms correctly
• in SwingGroupingInputHarvester, the group names are saved to the name of the respective component, such that they are identifiable later on in the lifecycle

[ctrueden]

• the font size is changed to 90% the regular font size to accommodate more controls in the inspector
• the MigLayout managers for all the inspector's constituents are changed to decrease white space in the inspector and make things more compact

Yaaaaas! Fight back against the "clean whitespace" propaganda!