always generate key if (EC)DH is used
Merge pull request #591 from prymitive/ssl_opts

always generate key if (EC)DH is used
added micros() api function
add ${HTTPS} to https_socket

https plugin sets ${HTTPS} so should https_socket proto -- admins can write consistent HTTP/HTTPS routing rules for both.
Merge pull request #593 from getcwd/patch-1

add ${HTTPS} to https_socket
Optimization for sweeper creation loop

cache_no_expire is a global flag, if it's set, return without further
check when trying to create sweepers.
Only allocate one sweeper thread

Thread is not cheap on Linux since it involves context switch in the
kernel. And allocating multiple threads is not necessary even on SMP
since the granularity of time is second.
Only scan cached items when there is expired one

This is an optimization for the sweeper algorithm. By remembering
the least expiration time, we can determine whether we need to go
over all items in a cache store. If we have to, we find the new
least expiration time by examining those that are not expired yet.
Merge pull request #594 from getcwd/master

cache/sweeper ehancement
Implement LRU for cache framework

If "purge_lru" option is used when creating cache store, the
"expires" parameter for cache_set/cache_update will be ignored.
Instead, all items are placed on an LRU list and when the store
is full, the least recent used one will be evicted.
Merge pull request #597 from getcwd/lru

Implement LRU for cache framework
added Yu Zhao to CONTRIBUTORS
the asyncio plugin (experimental)
 removed some useless debug
fixed corerouter error reporting
added asyncio build profile
fixed tornado plugin
another error report fix for the corerouter
the corerouter error reporting is still wrong :(
added php session support over cache