#1139 Show correct error message during load of SciTEStartup.lua (e.g. syntax error)

[Johannes Sasongko]

This is how SciTEStartup.lua is currently loaded and executed:

luaL_loadfile(luaState, startupScript.c_str());
if (!call_function(luaState, 0, true)) {
    host->Trace(">Lua: error occurred while loading startup script\n");
}

If an error occurs during the luaL_loadfile call (e.g. syntax error, OOM), the top of the stack contains a string (the error message) instead of the Lua code chunk. This causes the next line to attempt to call a string, resulting in this confusing error message:

attempt to call a string value
>Lua: error occurred while loading startup script

[Johannes Sasongko]

I'm not sure whether to use the Lua print function or to directly host->Trace the string; this patch uses the latter. Feel free to tweak it.

[Neil Hodgson]

Committed as [a9f6d5].

Can't see any benefit from using print over Trace.