0.5
 - Check for CURLM_CALL_MULTI_PERFORM to support very old versions of libcurl

0.4
 - Fixed a memory bug that could cause R to crash
 - Add curl_escape, curl_unescape
 - Add curl_version and curl_options

0.3
 - Add curl_download function
 - More efficient use of realloc
 - Fix for older versions of libcurl (e.g. Snow Leopard)
 - Add support for user interrupts while downloading (ESC or CTRL+C)
 - Fixed bug that caused GC to corrupt connection object
 - Refactoring and cleanup

0.2
  - add support for recycling connections

0.1
  - initial release
