1. Javascript decoder is now exported as a module using DracoModule()
function that needs to be instantiated on the client.
2. Updated Javascript example applications and README.md
3. Added normalization function to VectorD
4. Added support for converting a single signed value to symbol for
entropy coding and vice versa
5. Minor code cleaning
1. Add 'use strict'to example Javascript.
2. Small fixes to README.md.
3. Fix Draco compiler flag tests.
4. Fixed issue when number of quantized bits was to large.
5. Changed StartDecoding to return a value.
6. Check that num of attributes are not less than 0.
7. Check that the number of attributes is a valid value.
