Fix Lua 5.2 compatibility
Fix reload items/weapons

This fixes issue #35
Typo fix: enviroment -> environment
Temporary startup crash fix

Event::checkScript crashes after the single Lua state change with Lua
5.1 (doesn't happen with LuaJIT), backtrace:
0  0x00007f46c736537c in ?? () from
/usr/lib/x86_64-linux-gnu/liblua5.1.so.0
1  0x00007f46c736549e in ?? () from
/usr/lib/x86_64-linux-gnu/liblua5.1.so.0
2  0x00007f46c7365919 in ?? () from
/usr/lib/x86_64-linux-gnu/liblua5.1.so.0
3  0x00007f46c7365da8 in ?? () from
/usr/lib/x86_64-linux-gnu/liblua5.1.so.0
4  0x00007f46c735fced in lua_gc () from
/usr/lib/x86_64-linux-gnu/liblua5.1.so.0
5  0x00000000007cbce1 in LuaScriptInterface::tryCollectGarbage() ()
6  0x00000000007ca263 in LuaScriptInterface::closeState() ()
7  0x00000000007c9504 in LuaScriptInterface::~LuaScriptInterface() ()
8  0x00000000006d0ef0 in Event::checkScript(std::string const&,
std::string const&, std::string const&) ()
9  0x00000000006d0597 in BaseEvents::loadFromXml() ()
10 0x00000000008aee79 in ScriptingManager::loadScriptSystems() ()
11 0x000000000083fcc4 in mainLoader(int, char**, ServiceManager*) ()

Related issue: #41
Merge upstream/master & conflict fix.