redefined skilledge created skillfulness update function and signals

mc no selection bug fix, introduction to variables lesson

laptop loaddata 1st push, changed unit js script for non-logged in users

re-dump backup data

minor js changes

prerequisite field change in unit and curriculum

curriculum-unit fk changed

new lessons

negative number lessons

removed homepage lesson links, api changed

new lessons, question field

decimal ops lesson, reminder bug fix

order of operations, exponent lessons

privacy and terms, db backup

new lessons