Support permessage-deflate extension

[nkzawa]

This PR adds the permessage-deflate extension support to the module including the following features:

• Extension parameters (widow bits, no context takeover for both client and server)
• Configurations of extension parameters and memLevel (zlib)
• Enable extension by default
• All test cases of Autobahn Testsuite pass including WebSocket Compression

Things not included in the PR:

• x-webkit-frame-deflate (which Safari supports)
• Comprehensive architecture to add extensions flexibly

If these features also are required, I'm ready to add them.

Related: #34, socketio/socket.io#1148

[3rd-Eden]

woaaaaahhh @_@

[3rd-Eden]

@nkzawa I see that it fails on node 0.8 but overall the code looks good and I have no problem merging this and bumping ws to 0.6.

[andrewrk]

Wow, nice work. You beat me to it.

[nkzawa]

@3rd-Eden Thank you for reviewing. I will fix failing tests ASAP.

[rauchg]

<3 @nkzawa

[nkzawa]

@3rd-Eden Fixed. Please check again.

[3rd-Eden]

Thanks <3 -- Releasing as 0.6

[3rd-Eden]

The implementation seems to be really unstable, it's causing primus's test suite to fail and people have been reporting bugs of thrown errors as well: primus/primus#319 I'm going to release a 0.6.1 which disables permessagedeflate by default.

[nkzawa]

Ah, I'm sorry. I will tackle the problem.

[dscherger]

@nkzawa Is there any intention or plan to add support for x-webkit-deflate-frame even though it's deprecated, it would be nice for this to work with safari on ios and osx.