Removed references for SNTP.

The work in progress was posing serious problems for the Linux build.
Will put this functionality back later.
Added linux build.

The library code is now buildable using Cmake under linux. It is not the
easiest system in the work (have to specify the path to lwip checkout in
the CMake list), but its a start.
The linux build is testable.

The linux build of the project can now be used for testing. It opens a
tap pseudo interface on 192.168.0.9 (change if needed) and can be
accessed from the host.
Just changed Cmake's project and exe name.
Added info about linux build in the readme.
added a gitignore.