fix: #695

[cbmarini]

This resolves #695: in Compare1 the floats are now compared in raw mode if level>=1 (so if function arguments with floats are compared to each other). As a result, the following program:

#StartFloat 20
CFunction f;
Local F = f(1.00000000000000001)+f(1.0);
Print;
.end

results in

   F =
      f(1.0e+00) + f(1.0e+00);

This is because in raw form 1.00000000000000001 and 1.0 are different, even though the first exceeds the 20 bits of precision.

Furthermore, it fixes the bug that was in the following program:

#StartFloat 30
Symbol a,b;
CFunction f;
Local F = 1.0*f(a);
.sort
#endfloat

Local F = F + f(a);
Print;
.end

[coveralls]

coverage: 52.795% (+0.1%) from 52.682%
when pulling 7a05914 on cbmarini:fix-issue-695
into 25d6346 on form-dev:master.

[cbmarini]

As this fixes #695 and is an important fix for the floating point system, it is good to merge it already. I will make a separate issue about what the proper behaviour of the above program should be.