add json support for styles
add cose stub

@gerardohuck here's the stub for you
finish up #288, tested & documented
fix #287
remove console.log
Merge branch 'master' into navigator
add cy.renderTo()

@bumbu this is what you need

cy.renderTo( canvas2dcontext, zoom, pan)

idk if you'll need to set the pan but it's there if you need it :)
Merge branch 'master' into navigator
substitute thumbnail png with canvas