Numeric whitespace parsing is overly lenient

[kengruven]

The spec has several rules for where "numeric whitespace" can occur, but they don't seem to be enforced yet:

$ echo 'c1 -_1_____2_' | ./enctool convert -df cte
c0
-12

Most of the "Invalid" examples in the spec are actually parsed by enctool without error, so that would be a great test suite.