fixed edge label I/O
updated README
default UI prettification
render edge labels
made edge labels and tweaks menu rendering configurable in intro.js
added import/export to menu
reduced index page to one example
build
fixed css issues
delete objects by pressing delete key, plus minor content edits
updated README with todo list
index cleanup & enlarged working graph
added option to constrain edge weights to numeric values
fixed faulty logic for numeric edge constraint
updated README
minor aesthetic menu styling
added option to disable vertex addition/deletion
also disallow changing vertex names when vertex modification is disabled
bugfix - block checkbox action if user clicks Cancel for numeric edge toggle confirmation
added CSV import/export