Multiple cells screen: reset all button doesn't restart play

[BryceAG]

If the sim is paused on the multiple cells screen, then the reset all button is pressed, the sim will revert all values to default and clear the graph as it should, but the sim will remain paused and play will have to be pressed again.

related to phetsims/tasks#776.

Name: ‪Gene Expression Essentials‬ URL: http://www.colorado.edu/physics/phet/dev/html/gene-expression-essentials/1.0.0-dev.2/gene-expression-essentials_en.html Version: 1.0.0-dev.2 2017-01-30 19:21:44 UTC Features missing: touch User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36 Language: en-US Window: 1366x662 Pixel Ratio: 1/1 WebGL: WebGL 1.0 (OpenGL ES 2.0 Chromium) GLSL: WebGL GLSL ES 1.0 (OpenGL ES GLSL ES 1.0 Chromium) Vendor: WebKit (WebKit WebGL) Vertex: attribs: 16 varying: 10 uniform: 253 Texture: size: 8192 imageUnits: 16 (vertex: 16, combined: 32) Max viewport: 4096x4096 OES_texture_float: true Dependencies JSON: {"assert":{"sha":"a707328c","branch":"master"},"axon":{"sha":"1cf10281","branch":"master"},"babel":{"sha":"10f77fec","branch":"master"},"brand":{"sha":"0be722ee","branch":"master"},"chipper":{"sha":"f4cd39bf","branch":"master"},"dot":{"sha":"75380061","branch":"master"},"gene-expression-essentials":{"sha":"9e5baa27","branch":"master"},"joist":{"sha":"d15e6fab","branch":"master"},"kite":{"sha":"6059ebb0","branch":"master"},"phet-core":{"sha":"84747dff","branch":"master"},"phetcommon":{"sha":"1cb33196","branch":"master"},"query-string-machine":{"sha":"d8a4ff18","branch":"master"},"scenery":{"sha":"550df01a","branch":"master"},"scenery-phet":{"sha":"b04d8086","branch":"master"},"sherpa":{"sha":"785a536c","branch":"master"},"sun":{"sha":"d0708aa5","branch":"master"},"tandem":{"sha":"d9c124e5","branch":"master"}}

[phet-steele]

Fixed, thanks @BryceAG and @aadish.