Commit is being made to allow additions of GPL3+ code previously
un-addable. With these changes, contributions back to cuberite are
possible with the backporting exemtion, as well as adding stuff in
minetest with minetest code properly being read through and implimented
to upgrade it to GPL3 from GPL2.
project still has Apache2.0 license and credits to all its contributers, but now has the freedom of GPL3+ and all the code that can be implimented and shared with it.
Fixes#4040
* The TCP connection is now shutdown after OnBodyFinished
* Any open connections are closed when cNetworkSingleton::Terminate() is called.
* Removed ownership cycles in cUrlClientRequest
* Added a check to the test to ensure there are no leaks.
Stop using gdb on osx - was breaking the build
Add clang 3.5 build as travis now defaults to 5.0
Fix unknown-warning-option errors on AppleClang
ProtoProxy: Use nullptr
UrlClientTest: add override to callback destructor
Update jsoncpp to use nullptr
