removed todo messages - they have been done
deprecating FRAMEWORK_VERSION
replacing framework version with server version

* deprecating framework version
* this is a good rename because we might, in the future, move away
  from using a framework (use a .a or .dylib instead)
server and gem version compatibility check
updated changelog
added MIN_SERVER_VERSION and a Version class to compare versions
reformatted to use single quotes where possible
Merge pull request #350 from calabash/WIP/checking-server-version

WIP relaunch compares server version with gem version