Do not keep keep Gemfile.lock in version control

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Replace custom toolchain, Rake tasks with devtools

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Update specs to run with RSpec 2.12.x

* Use the standard DataMapper 2 spec structure for shared specs.

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Mark a OrderedSet#merge shared spec as pending

* The (previously-failing) syntax has been updated for RSpec 2.12.x.

  Needs clarification however, if this is the correct behaviour.

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Minor whitespace cleanup

Signed-off-by: Alex Coles <alex@alexbcoles.com>