Balances random map resources.

Attempts to avoid "invalid argument" errors in typed arrays by forcing
them to integer (see #658).
Removes script preloading from map generator (VFS is thread-safe now)
Removes thread checking from ScriptInterface file loading functions.
Adjusts starting entities in civ data.

This was SVN commit r9435.

source/scriptinterface/ScriptInterface.cpp

@@ -808,8 +808,6 @@ bool ScriptInterface::LoadGlobalScript(const VfsPath& filename, const std::wstri
 
 bool ScriptInterface::LoadGlobalScriptFile(const VfsPath& path)
 {
-	ENSURE(ThreadUtil::IsMainThread()); // VFS isn't thread-safe
-
 	if (!VfsFileExists(g_VFS, path))
 	{
 		LOGERROR(L"File '%ls' does not exist", path.string().c_str());
@@ -896,8 +894,6 @@ CScriptValRooted ScriptInterface::ParseJSON(const std::string& string_utf8)
 
 CScriptValRooted ScriptInterface::ReadJSONFile(const VfsPath& path)
 {
-	ENSURE(ThreadUtil::IsMainThread()); // VFS isn't thread-safe
-
 	if (!VfsFileExists(g_VFS, path))
 	{
 		LOGERROR(L"File '%ls' does not exist", path.string().c_str());