restructuring:move elements & clean js
add feature: delete file
add feature: task
update npm ignore
update: rename function & export f5
fix a bug
update: optimize algorithm
feature: add go-to-parent-dir feature
fix image holder

Conflicts:

	f5static/tree.js
Merge branch 'dev' into clean-master
sort files and folders by alphanumeric

Conflicts:

	lib/f5.js
	src/f5.coffee
fix: check out callback function