updated link to repository
added missing "Part" and "Chapter" in description
formatted description
converted tabs to spaces;
reordered methods and variables;
removed unncecessaries blank lines;
formatted code;
optimized imports
renamed "gltut" folder in "jgltut"
refactored the first two parts of gltut
refactored "Part III"
refactored part IV
fixed link to repository in header
reformatted code with 120 columns margin
changed top node text gltut in jgltut
renamed width and height params of reshape() in w and h