Improvement  of server selection GUI
Bug fix in SSAServerList  (NPE when querying the registry)
cleaned up code (removed not needed lines...)
documented changes
Changes in the query browser GUI, solved disappearing buttons problem
removed Exception for getData request returning an empty table
Documentation update
Reading multi-HDU FITS fix
Merge

Conflicts:
	splat/src/main/uk/ac/starlink/splat/data/SpecDataFactory.java
	splat/src/main/uk/ac/starlink/splat/iface/SplatBrowser.java
	splat/src/main/uk/ac/starlink/splat/vo/SSAServerList.java