Changes to fix #1816 - split up task for installing apps, use a custom
Tunable for the app replacement prompt
Conflicts:
	app-impl/src/main/java/org/cytoscape/app/internal/CyActivator.java
	app-impl/src/main/java/org/cytoscape/app/internal/ui/InstallAppsPanel.java

Change-Id: I86de2282b79fca4d46e8dfa9551441704f033082
Added error logging