TS-3064 Expose TS_EVENT_VCONN_ACTIVE_TIMEOUT in headers.
Add TS-3064 to CHANGES.
TS-3065 Remove"Transfer-Encoding" header when the error body was set by
ATS (e.g. plugin).
Add TS-3065 to CHANGES
Fix uninitialize variable compiler warning.

This closes #151
TS-3156: use a proxy allocated mutex
Fixing AddressSanitizer issue where sizeof(size_t) > sizeof(int).
Use libts pthread key wrappers
TS-3191 Add logic to better handle collisions with static producers.
Add changes
TS-3191: Confusion with HTTP_TUNNEL_STATIC_PRODUCER