Return write errors from default pong handler
Return write errors from default pong handler

Fixes issue #86.

y3llowcake/websocket,helight/helight_code,helight/helight_code,skyportsystems/websocket,helight/helight_code,helight/helight_code,helight/helight_code,helight/helight_code,gorilla/websocket,helight/helight_code,helight/helight_code,helight/helight_code,vonwenm/websocket-1,your-org/websocket