Project tree added. Available classes are:
folder 		---> 	usually folder
root 		---> 	root directory (main project directory)
sources 	---> 	"src" directory
package 	---> 	java package directory
runnable 	---> 	runnable class file
iml 		---> 	proj_name.iml file
lib 		--->	java external libraries directory
class		--->	usually java class file
interface	--->	java interface file
exception	--->	java exception file
annotation	---> 	java annotaton file