Change the network module of cpp-redis

[Cylix]

As explained in #29, some issues have been reported concerning cpp_redis.
Most of these issues are related to the network side of cpp_redis.

Instead of constantly fixing issues on that side, I decided to rewrite the network module as I was not satisfied with the current implementation (not satisfied by the design, maintainability was reduced over time and so on).

I decided to develop a TCP network library, Tacopie with an enhanced design and aiming to fix all the current issues (#38, #29, #24, #21, #19).

The current network module has been entirely removed.
Instead, tacopie has been integrated as a submodule of cpp_redis and is the new network part of the library.

The advantages of the submodule are the following:

• cpp_redis is now only focused on the protocol handling part, not on network issues
• networking issues and optimization will be dealt on tacopie repository
• installation of cpp_redis remains unchanged: everything is as simple as before

Another main advantage is that the network part may be changed for another library.
For now, tacopie is a pre-requisite of cpp_redis.
But in future versions, tacopie will become optional (packaged by default) and if the developer wants to integrate another network library, he will be able to (for example, Boost Asio).

There is no change in terms of features: library still provides the same features and work on both windows and Unix based platforms.

This constitutes a new release: v3.0.0.

Issues #38, #29, #24, #21, #19 will be closed as not relevant anymore.
If new problems are detected, please open new issues.

Objectives for next releases are:

• Providing more tests
• Improving performances (remove number of mutex locks for example)
• looking for IO Completion ports concerning network part on windows (for now, it is based on WSAPoll).

Enjoy!

[rmb338]

good job