Add plugins

Plugins:
	blocks/checklist
	blocks/my_target
	blocks/objectives
	blocks/progress
	course/format/topcoll
	grade/export/checklist
	mod/checklist
	question/type/ddimageortext
	question/type/ddmarker
	question/type/ddmatch
	question/type/ddwtos
	question/type/gapselect