Version 1.7.7

Fix for opacity parsing in svg with nested opacities #3747
Fix text initialization and boundingrect #3745
Fix line bounding box #3742
Improvement: do not pollute style object while typing if not necessary #3743
fix for broken prototype chain when restoring a dataless object on fill an stroke #3735
fix for deselected event not fired on mouse actions #3716
fix for blurriness introduced on 1.7.3 #3721