Merge pull request #35 from soniakeys/master

Simplify DNA type. Note this will break currently submitted solutions.
nucleotide-count: Model nucleotides as bytes

Unlike other languages, Go has two datatypes for single letters: rune
and byte. As our abbreviations for the nucleotides, A, C, G and T, can
all be ASCII-encoded, multibyte runes aren't needed.
octal: make more idiomatic

* extend the test file to require error cases.
* improve on the example solution
* change the name from ToDecimal to ParseOctal as it's more accurate
Merge pull request #30 from JohnGB/improve-octal

octal: make more idiomatic
Merge pull request #36 from sjakobi/nucleotide-count-bytes

nucleotide-count: Model nucleotides as bytes
Deprecate bottles in favour of beer-song

All the other languages have this as "beer-song" not bottles.
By renaming this we can get rid of the duplicate metadata files in
x-common.
grade-school exercise ported from ruby
Merge pull request #39 from soniakeys/grade-school

grade-school exercise ported from ruby
Merge branch 'master' of https://github.com/exercism/xgo