Change DSS / ref. image file-naming conventions! (Breaks some files)

When naming DSS (or other reference) images in the Observation
Planner, the following things have changed:

1. Quotes are removed from the object name. For example, the reference
   image for Hoag's Object will have the file name
   Image_HoagsObject.png -- this prevents failure on Windows and
   cleaner paths on Linux.

2. Naming convention for star images has changed to follow the
   standard RA/Dec format more closely. So instead of
   Image_HHMMSSDDMMSS-, we have Image_JHHMMSS-DDMMSS.png

3. The downloaded image files now have extension .png. Whenever KStars
   loads an older file without the extension, it will rename it so it
   has the extension. This will make the files more usable on Windows
   outside of KStars.

This breaks some things:

1. If the user had already downloaded images for stars, they are no
   longer going to be available in KStars and must be re-downloaded!

2. If the user had already downloaded images for Hoag's Object,
   Mayall's Object, Minkowski's Object, ... they are no longer going
   to be available in KStars and must be re-downloaded!

FIXED-IN:
CCMAIL: kstars-devel@kde.org