Setup connect timeout in curl.

Now curl will try to connect to docker daemon no longer then 10 seconds.
Remove debug printing.
Fix building with g++ 4.7.

G++ 4.7 removes default assignment operator from http_headers_t because of defined move constructor. Now i have defined assignment operators explicitly.
Docker plugin doesn't pool images by default.

If a user didn't specify registry in profile then the plugin will not pool images at all (will work with local images only).
Before it pooled images from dotCloud's registry and i think that this is a bad idea for a private cloud.
Avoid potential segmentation fault in docker client.

Before i filled libcurl's headers list as follows: append each header to vector and add pointer to content of the header in the vector to headers list.
But vector may reallocate memory when new items are added, that may invalidate some pointers in headers list.
Add docker plugin to debian/control.
Release 0.11.0.0.
Revert "Add docker plugin to debian/control."

This reverts commit 8a37bfc0b035c7e0f9507e2350a25a926b8627f1.
Temporary disable elasticsearch plugin.
Disable elasticsearch package building.
Fix connect timeout in docker plugin.

Docker client connects socket to the docker itself, this is not a work of curl. So setting of timeouts in curl is useless. I have implemented connect timeout via boost::asio timer, which stops event loop.
Remove debug logging.
Check if an asynchronous operation is aborted.

Handler of asynchronous operation mustn't perform any work, if it was aborted.
Merge branch 'v0.11' of github.com:cocaine/cocaine-plugins into v0.11

Conflicts:
	debian/control
Merge branch 'v0.11'

Conflicts:
	docker/docker_client.cpp
	docker/docker_client.hpp