Debugbar: message to say how to deactivate it
remove useless file
Fixes  #157
Update links in INSTALL
Release Jelix 1.6.0
Bumped version to 1.6.1pre
Fix: jException kept only the first line on multiline messages
Fixed version number
Merge branch 'jelix-1.6.x'

Conflicts:
	UPGRADE-TO-1.7.md
	lib/jelix/VERSION
	testapp/VERSION