Revert "add some stack-condition error checking to sqstdlib registration routines"

This reverts part of commit b9fc9317520586f281a52ec3613205cd6b2018d5.

sqstdlib/sqstdio.cpp

@@ -472,8 +472,6 @@ static const SQRegFunction iolib_funcs[]={
 
 SQRESULT sqstd_register_iolib(HSQUIRRELVM v)
 {
-    if(sq_gettype(v,-1) != OT_TABLE)
-        return sq_throwerror(v,_SC("table expected"));	
     SQInteger top = sq_gettop(v);
     //create delegate
     declare_stream(v,_SC("file"),(SQUserPointer)SQSTD_FILE_TYPE_TAG,_SC("std_file"),_file_methods,iolib_funcs);

sqstdlib/sqstdmath.cpp

@@ -88,8 +88,6 @@ static const SQRegFunction mathlib_funcs[] = {
 
 SQRESULT sqstd_register_mathlib(HSQUIRRELVM v)
 {
-    if(sq_gettype(v,-1) != OT_TABLE)
-        return sq_throwerror(v,_SC("table expected"));	
     SQInteger i=0;
     while(mathlib_funcs[i].name!=0) {
         sq_pushstring(v,mathlib_funcs[i].name,-1);

sqstdlib/sqstdstring.cpp

@@ -473,8 +473,6 @@ static const SQRegFunction stringlib_funcs[]={
 
 SQInteger sqstd_register_stringlib(HSQUIRRELVM v)
 {
-    if(sq_gettype(v,-1) != OT_TABLE)
-        return sq_throwerror(v,_SC("table expected"));
     sq_pushstring(v,_SC("regexp"),-1);
     sq_newclass(v,SQFalse);
     SQInteger i = 0;

sqstdlib/sqstdsystem.cpp

@@ -132,8 +132,6 @@ static const SQRegFunction systemlib_funcs[]={
 
 SQInteger sqstd_register_systemlib(HSQUIRRELVM v)
 {
-    if(sq_gettype(v,-1) != OT_TABLE)
-        return sq_throwerror(v,_SC("table expected"));
     SQInteger i=0;
     while(systemlib_funcs[i].name!=0)
     {