Update README.txt

README.txt

-BFC : a BrainFuck Compiler & interpreter
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+BFC : a BrainFuck Compiler
+--------------------------
 
 Build :
 -------
 
 Usage :
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-	./bfc [-h] [-e [-o a.out]] FILE.bf
+	./bfc [-h] [-o a.out] FILE.bf
 
 Options :
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  	-h print usage and exit
-	-e tell bfc to produce a elf file
-	-o with -e indicate the file to create
+	-o indicate the file to create (default is a.out)
 	FILE.bf the brainfuck source file to compile