Although this tutorial covered the process on a single image manually, much of this can be automated from the command line with relative ease. A few tools I recommend:
– GDAL and gdal_pansharpen.py ▻http://www.gdal.org/gdal_pansharpen.html
– landsat-util ▻https://github.com/developmentseed/landsat-util
– Rasterio ▻https://github.com/mapbox/rasterio