Added a bunch of new file natives.

Fixed possible corruption in snprintf when input buffer was bigger than output buffer and relaying on its retval.
Fixed all cases when the above situation happened.
Fixed _PrintToHL2Log not taking va_list in.

--HG--
extra : convert_revision : svn%3A39bc706e-5318-0410-9160-8a85361fbb7c/trunk%40279

core/systems/LibrarySys.cpp

@@ -289,6 +289,8 @@ void LibrarySystem::PathFormat(char *buffer, size_t len, const char *fmt, ...)
 	size_t mylen = vsnprintf(buffer, len, fmt, ap);
 	va_end(ap);
 
+	mylen = (mylen >= len) ? (len - 1) : mylen;
+
 	for (size_t i=0; i<mylen; i++)
 	{
 		if (buffer[i] == PLATFORM_SEP_ALTCHAR)