switchmods fixed session vars, saved to db in d2config class. Need to test d2s editor with modifyBit() function. need to fix app.js uniqueitems editor required fields on misc/weapons/armor

src/D2Functions.php

@@ -77,4 +77,9 @@ function strtobits(string $str): string {
 
 function swapEndianness($hex) {
     return implode('', array_reverse(str_split($hex, 2)));
+}
+
+
+function modifyBit(int $n, int $p, bool $b){     
+    return ($b ? ($n | (1 << $p)) : ($n & ~(1 << $p)) );  
 }