This allows to pass include paths and flags only to a given thirdparty
library, thus preventing conflicts between their files (e.g. between
opus and openssl which both provide modes.h.
This also has the nice effect of making the compilation command smaller
for each module as it no longer related to all other modules, only the
final linking brings them together.
This however requires adding manually the ogg include path in opus
and vorbis when building against the builtin ogg, since it is no longer
in the global env.
Also simplified template 'thirdparty_<module>_sources' to
'thirdparty_sources'.
"Core" modules like cscript, gdscript, gridmap, ik and virtual_script
still use the main env_modules, but it could be changed if need be.
Fixes the following problems.
A malicious client was able to contact another peer faking its identity
(even looking like he was the server).
A malicious client was able to force other client disconnections by sending
bogus system packets to the server.
NetworkedMultiplayerENet::get_packet was reporting the wrong size for the packet buffer exposing a potential buffer overflow in case of malformed/malicious packets
-Ability to set compression to ENet packets (check API)
-Fixed small bug in StringDB that lead to duplicate empty strings
-Added a new class, StreamPeerBuffer, useful to create your own tightly packed data
For reference, when you include a Windows header (be it directly windows.h or something that includes it)
put it at the end of the includes. it seems I forgot.
