fixes issue where custom headers couldn't be set for client connections
Updates transport code to use shared rather than raw pointers. references #293
Adds preliminary signaling to iostream transport of eof and fatal transport errors
Deprecates iostream transport `readsome` in favor of `read_some`

which is more consistent with the naming of the rest of the library.
adds documentation notes about when fatal_error and eof methods showed up
refactor iostream read completion to remove memory leak
updates iostream tests for new safer/less leaky API
additional debug log detail
removes internal connection tracking mechanism from endpoint
catch test error condition better
adjust transport async_accept and async_connect to use connection_ptr instead of connection_hdl

prevents a newly created connection_ptr from being destroyed
immediately after accepting or connecting.
update changelog
Re-introduces strands to asio transport
replaces sha1 library with a more clearly licensed project references #294
Updates COPYING file to include all bundled licenses references #294
updates changelog
removes unused variable set per static analysis
Eliminate spurious expired timers in certain error conditions references #295
HTTP requests ending normally are no longer logged as errors. references #294
updates license information for UTF8 validation logic references #294