String - DeDup

Syntax:
= DeDup(Text [, Character] )

Description:
Deduplicates repeating characters and replaces them with a single character.  

Text : string to process
Character : characters to deduplicate (" " is the default)

Example:
Remove duplicated spaces from the string "hello                world":
=DeDup("hello                world")
returns: hello world

Remove duplicated exclamation marks from the string "This is great!!!!!!!!!!!":
=DeDup("This is great!!!!!!!!!!!", "!")
returns: This is great!