improve code readability

and remove 2 class in ofxTerrain, they will be placed at core game
module
roughly implement ofxTerrain
ofxTerrain, new design, layered
roughly implement ofxTerrain

build opengl data & render function
ofxTerrain, generate base layer data
ofxTerrain, calculate vertex uv
implemented paint tile feature
minor optimize
minor optimize
correct coordinate

terrain tile on xz plane not xy plane
terrain test 1 failed, tile not drew correctly
terrain test 1, 2 passed, fix color bug
optimize sprite renderer
add some genius code
Merge branch 'master' of https://github.com/ngoaho91/BambooOF