Update version to alpha6.2
Fix store_variable() issue on storing a array/object/mapping.
Set TCP_NODELAY on both user sockets and LPC sockets.

TCP_NODELAY should decrease latency for normal user.

For LPC sockets, Make sure you call socket_write() with a
reasonable size of buffer (more than 1K).
Merge pull request #127 from sunyc/master

Changes for alpha6.2