seq defaults to a minimal fixed point format that does not lose

seq defaults to a minimal fixed point format that does not lose
information if seq's operands are all fixed point decimal numbers.
You no longer need the `-f%.f' in `seq -f%.f 1048575 1024 1050623',
for example, since the default format now has the same effect.

seq now lets you use %a, %A, %E, %F, and %G formats.

seq now uses long double internally rather than double.