Resolves the given String containing some switch chars in form of backslash 
 to a string with the appropriate character codes.
 In the result String all char-pairs beginning with backslash are replaced by
 one char. If the String doesn't contain backslashes, the method returns the input string
 in a as soon as possible calculation time.
 
 - \n\r\t\f\b will converted to the known control character codes:
 
- \n newline 0x0a
 
- etc TODO
 
- \s will converted to a single space. It is usefull in input situations
     where a space will have another effect.
 
- \a will converted to the code 0x02, known in this class cStartOfText.
     It is usefull wether a String may be contain a code for start of text.
- \e will converted to the code 0x03, known in this class cEndOfText.
- \x0123 Convert from given hex code TODO
 
- \\ is the backslash itself.
 
- All other chars after backslash will be converted to the same char, 
     at example "\{" to "{". Don't use this feature for normal alphabetic chars
     because some extensions in a future may be conflict with them. But this feature
     may be usefull if an input text uses the special characters in a special way.