Lock down RSpec version

... in preparation for upgrading to RSpec 3.

This should also fix spec failures on Travis, which now defaults to RSpec 3
unless another version is specified.
Clean up RSpec deprecation warnings

> `be_true` is deprecated. Use `be_truthy` (for Ruby's conditional semantics) or
> ``be true` (for exact `== true` equality) instead.
Bug fix. Economic allows number to be string on occasion.
Rebase
Use be_truthy.
Use be_truthy