libgearman server option handling

[Keyur]

Server options need to be preserved across connect/disconnect cycles (as seen in https://bugs.launchpad.net/gearmand/+bug/1098409). They need to be resent 'automatically' every time a reconnect happens internally inside libgearman.

The current API design does not allow for this; the caller need to be aware and "re-set" the option by calling gearman_client_set_server_option() again.

The proposed patch works by storing the option and delaying the actual network-io until an "real" data-packet needs to go across to the server.

Along with the benefit of graceful reconnection handling, it will also fix an inconsistency: consider a client with multiple servers added in. In the old design, if one of the servers was down but the other was up, the API call gearman_client_set_server_option() would fail hard.

This is unlike how say the gearman_client_do_background() API works. It will try to send the request over to all servers and only return failure if all of them are down. By delaying, we emulate this behavior.

In case a bad option is set, a new error code GEARMAN_INVALID_SERVER_OPTION is returned.

[Keyur (keyurdg)]

I'm stupid. Missed the 2 new files server_options.*

Attached now :)

[Keyur (keyurdg)]

Patches are based off of v1.0.2