ESLint: global variables

[felixfbecker]

I just quickly ran eslint over the source and it exposed several places of undeclared variables, which means the variables get assigned to the global scope. There is also inconsistent indentation, use of quotes, semicolons, but I think these are important to fix:

    7:7   error    "oldExport" is defined but never used                    no-unused-vars
   74:58  error    "chartOptions" is defined but never used                 no-unused-vars
   97:14  error    Empty block statement                                    no-empty
  132:7   error    "menuItem" is defined but never used                     no-unused-vars
  197:35  error    "dotdotdot" is defined but never used                    no-unused-vars
  228:62  error    "chartOptions" is defined but never used                 no-unused-vars
  302:11  error    "optionToCopy" is not defined                            no-undef
  303:34  error    "optionToCopy" is not defined                            no-undef
  304:52  error    "optionToCopy" is not defined                            no-undef
  304:87  error    "optionToCopy" is not defined                            no-undef
  375:81  error    Unnecessary semicolon                                    no-extra-semi
  400:7   error    "blobObject" is not defined                              no-undef
  401:41  error    "blobObject" is not defined                              no-undef