remove all YUI dependency

• Changes from 10.2.0 to 10.3.0
  • remove YUI library dependency
  • LICENSE.txt
    • remove YUI license
  • src/base64x.js
    • add extendClass function to replace YUI class extend
  • src/*.js
    • replace YAHOO.lang.extend to extendClass all
  • src/keyutil.js
    • change to raise exception in KEYUTIL class with Error class
  • src/asn1x509.js
    • API document update for Extesions and CRLReason class
  • npm_util/package.json
    • fix dependencies (#482)
  • test/qunit-do-*.html
    • updated to follow above
  • test/qunit-do-base64x-class.html added
    • test for extendClass function