context: unify libwebsocket_create_context()'s return

Signed-off-by: Alejandro Mery <amery@geeks.cl>
Add dummy tracing support [DEBUG]

Signed-off-by: Alejandro Mery <amery@geeks.cl>
alloc: count malloc/realloc/free [DEBUG]

Signed-off-by: Alejandro Mery <amery@geeks.cl>
Revert "alloc: count malloc/realloc/free [DEBUG]"

This reverts commit d6e9ec9206d07c3e69ee8665d375a807f837a3d5.
introduce info->event and info->e to select and configure a backend

Signed-off-by: Alejandro Mery <amery@geeks.cl>
libev: Add test-client-libev flavour of test-client

Signed-off-by: Alejandro Mery <amery@geeks.cl>
libev: Add test-server-libev flavour of test-server

Signed-off-by: Alejandro Mery <amery@geeks.cl>
introduce context->event_ops

Signed-off-by: Alejandro Mery <amery@geeks.cl>