Add infrastructure (interfaces, some realisation) for filtering tasks
Add possibility to hide/show finished. No hide when check finished

Reformat code.
on-fly save
Merge remote-tracking branch 'remotes/origin/saveFinished' into develop

Conflicts:
	src/com/example/Tasker/view/activity/Tasker.java

Tasks fadeout time was added.
Preferences class
Merge branch 'hideFinished' into develop