WebSocket++/0.3.0-alpha4

• HTTP requests ending normally are no longer logged as errors. Thank you Banaan
  for reporting. #294
• Eliminates spurious expired timers in certain error conditions. Thank you
  Banaan for reporting. #295
• Consolidates all bundled library licenses into the COPYING file. #294
• Updates bundled sha1 library to one with a cleaner interface and more
  straight-forward license. Thank you lotodore for reporting and Evgeni Golov
  for reviewing. #294
• Re-introduces strands to asio transport, allowing io_service thread pools to
  be used (with some limitations).
• Removes endpoint code that kept track of a connection list that was never used
  anywhere. Removes a lock and reduces connection creation/deletion complexity
  from O(log n) to O(1) in the number of connections.
• A number of internal changes to transport APIs
• Deprecates iostream transport readsome in favor of read_some which is more
  consistent with the naming of the rest of the library.
• Adds preliminary signaling to iostream transport of eof and fatal transport
  errors
• Updates transport code to use shared pointers rather than raw pointers to
  prevent asio from retaining pointers to connection methods after the
  connection goes out of scope. #293 Thank you otaras for reporting.
• Fixes an issue where custom headers couldn't be set for client connections
  Thank you Jerry Win and Wolfram Schroers for reporting.
• Fixes a compile error on visual studio when using interrupts. Thank you Javier
  Rey Neira for reporting this.
• Adds new 1012 and 1013 close codes per IANA registry
• Add set_remote_endpoint method to iostream transport.
• Add set_secure method to iostream transport.
• Fix typo in .gitattributes file. Thank you jstarasov for reporting this. #280
• Add missing locale include. Thank you Toninoso for reporting this. #281
• Refactors asio_transport endpoint and adds full documentation and exception
  free varients of all methods.
• Removes asio_transport endpoint method cancel(). Use stop_listen() instead
• Wrap internal io_service run_one() method
• Suppress error when trying to shut down a connection that was already closed