todo

[x] fix bug: faces missing on chunk boundaries
[x] do not output blocks for non-block blockIds (torches, flowers...)
[x] show progress on chunks x/y chunks processed
[x] run processing and enclosedBlock fetching in separate goroutines
[x] colors for all visible block types
[x] store EnclosingSides instead of ChunkSides. That way when the chunk is processed, the side information can be discarded immediately
[x] add object that manages writing out the obj and mtl files
[x] add version number and scripts to bump the version number
[ ] center on spawn point, not chunk (0,0)
[ ] make processBlock() return the data rather than calling the process methods itself. Rename current method.
[ ] unit tests
[ ] godoc
[ ] refactor: introduce a 'preferences' type
[ ] refactor: tell the ntb file parser what it should extract and have it return that data (easy to pull out say, the spawn coords)
[ ] add flag to output all water faces / blocks (deep water darker)
[ ] add flag to output all blocks (particularly for prt mode)

[ ] transparent blocks (torches, glass, redstone paths...) aren't part of the 'surface' and must include the blocks under them
[ ] write out txt file with mcobjBlockIds, blockIds, data values, and interpretation of those values IOT make it easy for prt users to create meshes
[x] read mtl and blocktypes data from txt files (means I don't have to do a new release to keep up with minecraft)

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[x] Move block Id's, colours, etc. into external text file so you dont have to recompile to tweak something :P

[x] Remove specific check for (blockId == 0) for empty. Also remove "hide stone" flag. Do both through special empty flag in json

 - black glass (try removing glass faces adjacent with other faces)
 - compile as separate units (private stuff can only be seen when compiled at the same time)

 - Non-cubed blocks
    - crosses for saplings, sugar cane, fire, red/yellow flowers, red/brown shrooms, wheat
    - snow blocks are 1/8th height (Full height and 1/8th height snow blocks have the same ID)
    - calculate water/lava heights
    - farm land is 7/8th height
    - cake, half-blocks, pressure plates (stone, wood), fence posts, doors (wood, metal), ladder, tracks, redstone wire, signs, wall signs, steps, buttons, beds, redstone repeaters
 - Calculate data for grass, fenses, restone wire, chests, water/lava, portals
 - 64-bit Linux builds
 - 3DSMax output or 3DSMax fixer
 - Center on spawn location
 - Center on player location
 - open source mcobj
 - 'chunk slice' renders
 - add FBX output format (http://usa.autodesk.com/adsk/servlet/pc/index?id=6837478&siteID=123112)