====== SaveFile ======
Stores the value in a file, with the parameters:
* **fileName**: the file name.
* **overwrite**: the content to be written to the file.
* **overwrite**: defaults to true(). Determines whether an existing file will be deleted (overwritten) or the mapping will end with an error.
* **base64Decode**: defaults to false(). If set to true(), the content will be considered as base64 content and stored decoded.
The length of the written file in bytes is returned.
==== Syntax: ====
SaveFile ( string fileName, string content, bool overwrite, bool base64Decode )
==== Example ====
SaveFile("D:\temp\MyDoc.txt", "The text in the file")
SaveFile("D:\temp\MyDoc.pdf", $Base64Content, true(), true())
SaveFile("D:\temp\MyDoc.pdf", LoadFile("D:\temp\MyInputDoc.pdf", true()), true(), true())