support octal in writef/readf
 fix unused variable
 add octal tests
include octal as base specifier
Octal print test now passes
Merge remote-tracking branch 'upstream/master' into format-octal
Merge pull request #460 from mppf/format-octal

Support octal in readf/writef

I've added octal support to readf/writef.
Lydia's future now passes and demonstrates two octal printing variants.

Tested against 'make check', test/io/ferguson and Lydia's octal test.