Fix Issue #2, Add Stay-Awake mode

New Features:

• Stay Awake mode: If this mode is activated (by checking in the initial settings dialog, see below), CiliaQ Preparator will mimic a mouse motion once in a while to prevent your computer from sleeping (particularly helfpul for Mac users because completely disabling sleep mode in the Mac OS is not always possible).

Bugs fixed:

• Issue #2 is fixed now - To this end, for 2D images, a 2D "Fill Holes" method was implemented into Canny3D.
• When using the previous version, issues could have appeared when using Canny3D and when ImageJ's core-preference "Black background" was set to false. From this version on, CiliaQ Preparator makes sure that ImageJ's core-preference "Black background" is always set to true for any image processing steps performed by CiliaQ Preparator.