Removed redundant and mistaken information from some spreadsheets.

- Removed the "Using prices from" text which was redundate since the dropdown
  menus keep the locatinons used in the current request.
- Removed the formulas because all spreadsheets had the ore mining formulas and
  even that was incomplete and outdated. Formulas may come back later
Improved the Ore Mining spreadsheet

- Applied bootstrap theme.
- Improved readibility in the controller method and the Variation model
- Removed the volume column from Mineral since all minerals have the same
  unit volume and added a VOLUME constant to the model.
Missed a small change on the last commit to PlanetaryCommodity model