Hotfix for AI-640: Added ad hoc optimization for common export case
AI-640 Moved export to excel process to a background task
Merge branch 'release' into version4

Conflicts:
	server/src/main/java/org/activityinfo/ui/client/page/entry/DataEntryPage.java
Merge branch 'version4' of github.com:bedatadriven/activityinfo into version4
AI-579 Added migrator main method to help migrate existing mysql databases