v1.6.1

• andreftavares Added method to remove HoverDetail's mouse listeners.
• GermanBluefox Remove error if no jQuery.
• gaganawhad Add default value for renderer
• michelle-stripe HoverDetail should default to being inactive.
• stuartnelson3 Add Rickshaw.Graph.Dragzoom
• mikeatlas use prepend/append files for UMD support
• tamasgoga fixed stacked area chart hover detail bug in firefox
• Mokeponi Fixes issue with negative values between 0 and -1
• Bhashit Create a locally scoped copy of the loop-index var to prevent accessi…
• cesine add Rickshaw.version