updated changelog for 2.1 and 2.2
Added 2.1 and 2.2 releases to changelog
STUN check fixes. Re Issue #816

 - Now STUN server is returning what should be the outer port on which
   it could listen to the OpenBazaar node (a random one)
 - The --server-port argument is ignored unless --disable-stun-check is passed.

The reason being default behavior is configured so that OpenBazaar will try to establish all its connections without user intervention.
A user that knows on what port they want OpenBazaar to run and who is manually forwarding ports should then read the help and understand the port is being ignored due to the default STUN check openbazaar attempts.

  Try setting a manual port, the one you have set on your router.
  `openbazaar --disable-stun-check --server-port <your_port> -d --log-level 10 start`

  Try letting openbazaar do its work by looking up a valid incoming server port via STUN, and to automatically do the UPnP port mapping on such port.
   `openbazaar start`
Merge pull request #845 from gubatron/stun-fix-attempt

STUN check fixes. Re Issue #816
Fix issue 861: configure.sh fails on mac os x
Merge pull request #878 from benemorius/fix_configure_script_for_mac

Fix issue 861: configure.sh fails on mac os x
Move exception out of crypto_util
Refactor guid exists check
Merge pull request #880 from hoffmabc/decline-legacy-msgs

Move exception out of crypto_util
Merge pull request #876 from gubatron/changelog-sync-issue-831

Changelog sync - Issue #831
Remove zlib dependency and usage
Return early when decryption fails. Fix #883.
Merge pull request #885 from Renelvon/fix_unbound

Return early when decryption fails. Fix #883.
Up the version
Merge pull request #877 from hoffmabc/hotfix-compression

[Hotfix] Remove zlib compression calls
Merge branch 'master' into backmerge-0.2.3

Conflicts:
	configure.sh
	node/connection.py
	node/transport.py

* Immaterial conflicts in configure.sh.
* Immaterial conflict in node/connection.py: Since #839 the message is
  sent uncompressed by default.
* Conflicts in node/transport.py due to various refactorings, mostly the
  PeerListener extraction (#678): _on_raw_messge now resides in
  node/connection.py and it does not decompress the message since #839.
Update changelog and README.
Merge pull request #886 from Renelvon/backmerge-0.2.3

Backmerging master 0.2.3
Reduce threading
Check for unconnected Bitmessage API