week 4 assignment (patmat)
weight, chars and times method implemented
Merge remote-tracking branch 'origin/master'

Conflicts:
	funsets/.idea/copyright/profiles_settings.xml
	funsets/.idea/misc.xml
	funsets/.idea/scala_settings.xml
	funsets/.idea/vcs.xml
	funsets/.idea/workspace.xml
	funsets/progfun-funsets.iml
	funsets/project/progfun-funsets-build.iml
makeOrderedLeafList implemented
makeOrderedLeafList corrected and refactored
singleton implemented
combine implemented
until implemented
createCodeTree implemented