Some minor bugs to fix later

[johnd0e]

(It's a reminder for myself to fix the bugs later, during refactoring)

[johnd0e]

https://github.com/IITC-CE/ingress-intel-total-conversion/blob/256f9c53a866a254b40e40b1f766e58b4d2a89f4/main.js#L28 TypeError when user is not logged in, see https://github.com/iitc-project/ingress-intel-total-conversion/pull/1249#discussion_r274823201

[johnd0e]

https://github.com/IITC-CE/ingress-intel-total-conversion/blob/256f9c53a866a254b40e40b1f766e58b4d2a89f4/plugins/farms-find.user.js#L254

1. This part of code executed on script initial load, before setup, so google could be not defined
2. I doubt that we really need to change prototype
3. I doubt that we ever need google api for this plugin. And what if current baselayer is not google (need to check).

[johnd0e]

https://github.com/IITC-CE/ingress-intel-total-conversion/blob/256f9c53a866a254b40e40b1f766e58b4d2a89f4/code/utils_misc.js#L411-L412

1. layerGroup._leaflet_id is private property
2. And it does not correspond to layerChooser._layers index, so this function just cannot work properly
3. Actually it is not used in any known plugin
4. All this layerChooser numerous stuff needs to be refactored and placed in single class (instead of random parts of source files).

[johnd0e]

Here is missed styler for default ingress map:

{featureType:"road",elementType:"labels.icon",stylers:[{invert_lightness:!0}]}