Create PacketError exception and use it with ACTIVEOBJECT_REMOVE_ADD handler which can be unreliable

Remove software exception translator function, simplifying exception handler
macros.  FatalSystemExceptions are left unhandled.

Don't use TOSERVER_RECEIVED_MEDIA but TOSERVER_CLIENT_READY as indicatio for client ready
Handle clients with protocol version < 23 (almost) same way as before
Make client tell server about it's version
Add client state to not send bogus player position updates prior init complete
Add access to statistics information (peer connction time,rtt,version)
Fix clients standing stalled in world while preloading item visuals (new clients only)
Add get_player_information to read client specific information from lua

This reverts commit 3f376a09.

Rename try* non exceptioning functions to *NoEx

Switch the license to be LGPLv2/later, with small parts still remaining as GPLv2/later, by agreement of major contributors

--HG--
rename : src/licensecomment.txt => licensecomment.txt