cache compiled templates

also remove dashes from template names
migrate styles to Sass
update templates and makefile
add edit button on argument ports
show argument dialog on all ports

split subeditor class to separate files
implement argument dialog
method to remove argument port form node
implement argument deletion from function
use id on input
hide add argument button if there is no more room
add interface for renaming port
implement renaming of arguments from functions
remove margin from add button when arg list is empty
allow control to accept and transmit values
use mixin methods on operators
don't allow step greater than range
fix #27 step doesn't affect incoming values in slider
add new sketch button to toolbar
prevent multiple loop starting
cache reference to subeditor on creation