improved usage and fixed customization details
techtree now goes into tech-tree div instead of appending to document
added config option to set image dir
demo now works with techtree loading in tech-tree div
tree now in good working shape with new changes; partiall implemented fix to #18
fixes #9
added 'you cant touch this' animation
removed unneeded text, added comment on transition().each()
organized and improved API methods
transition time is now a config option
added NoNo animation to clicks on disabled nodes
merged from master