Add support for map.fitbounds

When it is difficult to calculate the correct zoom level to show an specific area of the map, google maps allow the use of Map.fitBounds. It basically needs only the NE and SW coordinates: https://developers.google.com/maps/documentation/javascript/reference/3/map#Map.fitBounds

I have added the support for it in my fork, and I would like to do it in the main branch if approved. My only questions is. Should this be added as a separate function? something like def fit_bounds(self, nelat, nelng, swlat, swlng): or as a different way to initialize the map. That means providing NE and SW instead of center_lat, center_lng, zoom.

[frslm]

I’ve just merged this into master in #153, you can set it by passing in a bounds literal when creating a GoogleMapPlotter object:

import gmplot

fit_bounds = {'north':37.832285, 'south': 37.637336, 'west': -122.520364, 'east': -122.346922}
gmap = gmplot.GoogleMapPlotter(37.766956, -122.438481, 13, fit_bounds=fit_bounds)

[keithstellyes]

Right as you said that I found this PR and got it working:

https://github.com/vgm64/gmplot/pull/12/commits/2b5b2d634534dd2b31fc8eae566bffdc22a579d5

However that code in that PR is slightly bugged in that SW is supposed to go first, NE.

Thanks either way though! Appreciate it 😃