Revert "Fix assignment."

This reverts commit 907f856034461b6531a0e18795de2e15740e5f02.
Revert "New way to handle Streams"

This reverts commit 88fa9b6b2aedbf7d3038362f0e776aed9333980a.
Improvements in Digest authentication and 'challenge' grammar.
Forgot to remove a "console.log" into Grammar.pegjs.
Merge branch 'authentication' of github.com:versatica/JsSIP into authentication