Reset translation and scale when graph input changes in demo
Reset translation and scale when graph input changes in demo

Previously the demo keeps the same translation and scale until the user
tries to interact with the graph at which point it "snaps" back to the
original values.

This change automatically resets the translation and scale each time the
graph input is changed.

Fixes #56.

leMaik/graphlib-dot,cpettitt/dagre,cpettitt/graphlib-dot,ENCODE-DCC/dagre-d3,9n/dagre,GerHobbelt/dagre,dagrejs/dagre-d3,rwl/dagre_charted,harsha-mudi/dagre-d3,git-ashish/dagre-d3,lmcorbo/dagre,tylingsoft/dagre-layout,git-ashish/dagre-d3,dagrejs/dagre-d3,shelsonjava/dagre,9n/dagre-d3,shelsonjava/dagre,cpettitt/dagre-d3,rwl/graphlib_dot,cpettitt/graphlib-dot,kdawes/dagre,9n/dagre-d3,cpettitt/dagre-d3,cpettitt/dagre,GerHobbelt/dagre,harsha-mudi/dagre-d3,cbfx/dagre-d3,cpettitt/dagre-d3,leMaik/graphlib-dot,lmcorbo/dagre,9n/dagre,GerHobbelt/dagre,shelsonjava/dagre,rwl/dagre,9n/dagre-d3,lmcorbo/dagre,git-ashish/dagre-d3,cbfx/dagre-d3,abduld/dagre,witcxc/dagre,abduld/dagre,rwl/dagre_charted,dominiek/dagre-d3,abduld/dagre,ENCODE-DCC/dagre-d3,kdawes/dagre,witcxc/dagre,kdawes/dagre,rwl/dagre_charted,dominiek/dagre-d3,9n/dagre,dominiek/dagre-d3,cpettitt/dagre,tylingsoft/dagre-layout,cbfx/dagre-d3