toInt and toUint passed base 0 to strconv, which infers the base from the
literal the way the Go compiler does. A zero-padded CSV field was then
read as octal: 08 and 09 failed with invalid syntax and 010 silently
parsed as 8.
Pass base 10 at both call sites. Go-style prefixed literals such as 0x1f
are no longer accepted; they were undocumented and untested, and cannot
be kept without keeping the octal reading of 010 as well.
Closes#182
