Update readme to include link to Opera store
Update readme to include link to Opera store

duylam/octotree,jamez14/octotree,SampleLiao/octotree,crashbell/octotree,duylam/octotree,zhutaorun/octotree,mikestaub/octotree,buunguyen/octotree,Brightcells/octotree,treejames/octotree,guidiego/octotree,FroggyStyle/octotree,Ephemera/octotree,treejames/octotree,crashbell/octotree,Brightcells/octotree,ldnguyen58/octotree,mikestaub/octotree,ldnguyen58/octotree,Ephemera/octotree,zhutaorun/octotree,buunguyen/octotree,jamez14/octotree,SampleLiao/octotree,FroggyStyle/octotree,guidiego/octotree