Release v0.2.2

Default formatting is set to dec (decimal) if formatting attribute is not provided.

Example: those two statements will result in the same output now

var format = require('biguint-format');

format([0x2A, 0xFF, 0x1E, 0x22, 0x11, 0x30, 0x12, 0x2F], 'dec');
format([0x2A, 0xFF, 0x1E, 0x22, 0x11, 0x30, 0x12, 0x2F]);