Fix tensor cleanup and orphan event listener (#171)

Closes: #166

Signed-off-by: Justin Georgi <justin.georgi@gmail.com>

Reviewed-on: #171

src/pages/camera-mixin.js

@@ -25,12 +25,14 @@ export default {
     },
     closeCamera () {
       this.cameraStream.getTracks().forEach( t => t.stop())
+      this.cameraStream = null
       this.videoAvailable = false
     },
     captureVidFrame() {
       const vidViewer = this.$refs.vid_viewer
       vidViewer.pause()
       let tempCVS = document.createElement('canvas')
+      tempCVS.id = 'temp-video-canvas'
       tempCVS.height = vidViewer.videoHeight || parseInt(vidViewer.style.height)
       tempCVS.width = vidViewer.videoWidth || parseInt(vidViewer.style.width)
       const tempCtx = tempCVS.getContext('2d')