Adding ORIGIN field to more layers

[hellricer]

Introducing ORIGIN field to Forests, Lakes, Cities & Towns layers.

Also did a small clean-up of LAYER, GM_LAYER and GM_TYPE fields in these and Rivers layer.

In all cases they were either all set to the same value or they just mirrored other fields. I replaced them with single field called TYPE.

• Forests

  • decided to "canonize" new forests from Baynes' map (revealed in 2015 to had been suggested by Tolkien himself). (See [1], [2])
    • namely two forests in Dunland, four forests between Gwathló and Isen, forest in Drúwaith Iaur and forests west and north of river Lefnui.
    • the MERP versions of Trollshaws and forests in southern Blue Mountains are quite different in shape. For these I basically eyeballed, trying to make it resemble original maps as much as possible...
  • fixed invalid geometries
    • there was a ton of self-intersecting polygons in this layer, but turns out there's very easy fix for it - just create a buffer with distance set to 0. Works like charm.

• Lakes

  • added missing Bywater Pool
  • renamed shapefile from 'Lakes2' to 'Lakes'
  • fixed invalid geometries

• Towns

  • merged all MERP towns & villages from CombinedLayers into the layer

• Cities

  • dtto

• Rivers

  • dtto + corrected shapes of named rivers according to the maps

This pull-request also closes issue #3.

[ghost]

Thanks hellricer!