Add encoding @functions for custom HTML, XML and JSON

When building custom HTML, XML or JSON, there are a few character, that needs escaping.

@HTMLEncode

For doing HTML encoding, I use this to encode a text field/string:

text := "B&O";
_from := "&":"<":">":"\"":"'";
_to := "&amp;":"&lt;":"&gt;":"&quot;":"&#39;";
@ReplaceSubstring(text ; _from; _to)

It would be so much nicer, if I could write:

text := "B&O";
@HTMLEncode(text)

The output would be:

"B&O" 

@XMLEncode

A little different for XML

_from := "&":"<":">":"\"":"'";
_to := "&amp;":"&lt;":"&gt;":"&quot;":"&apos;";
@ReplaceSubstring(text ; _from; _to)

Could become:

@XMLEncode(text)

@JSONEncode

_from := "\\":"\"":"/":"        ":@Newline;
_to    := "\\\\":"\\\"":"\\/":"\\t":"\\n";
@ReplaceSubstring(text; _from; _to)

Please note that the second to last character in the _from list is a tab character.

Could become:

@JSONEncode(text)