Make FX able to handle SCC

Some other small changes.

	- Constant-1 (a + !a)
	- Divisors "a + !ab" and "a!b + b" are equal to "a + b"
Change the way divisors are printed.
Removal of dead code from fx.

Handling D1C and SCC in FXCH

Enables FXCH to handle Distance-1 cubes (D1C) and Single Cube Containment (SCC) as by product of extraction.

D1C: Whenever they appear a constant divisor (x! + x)  will be created and handle as any other divisor.
SCC: Will be taken care of as soon as they appear.