newRPL: inexact numbers

[Claudio L.]

In the other thread about symbolic numbers, the trailing dot was used to specify "exact" vs. "approximated" numbers.
This same concept can be used to achieve what this thread was proposing: if any operation comes up with the "inexact" flag, its result will be an "approx." number, which will be displayed with a trailing dot.

The result of any numeric operation will be an "approx" number if either:
a) The result of the operation has the "inexact" bit set
b) Any input to the operator is an approx. number

2 INV --> 0.5 (exact)
2. INV --> 0.5. (approx)
3 INV --> 0.33333333. (approx)

Since this had to be implemented for the CAS to work properly without an exact/approx. mode, the overhead was already there.

I already implemented it and is being tested.
Next demo will come with this feature.