Fix failing tests in Travis CI environment

Fixes #174. There is a bug in ActiveSupport 3.x when adding durations,
which truncates extra precision that is sometimes present in time.nsec
Cleanup
Occurrence to_s takes format option to comply with ActiveSupport
Remove StripeMe
Match documentation with reality

The correct behaviour is tested and described in monthly_spec.

Fixes #191
Resetting count should clear validation

The "should raise_error" test was not working with newer RSpec. It
should probably just be nil and not raise an error anyway.
Split up confusing specs
Delete redundant test

This is well tested in monthly_spec already

Fixes #192
Move deprecated into IceCube namespace

Closes #188
Mixin belongs in the inner Validation classes, not here
Use recent versions of RSpec for testing
Make RSpec 2.14 happy: stubs are doubles
Clean up metaprogramming for readability
Inline simple conditions
Standardize the exceptions that we raise
Put helpers in a module to clean up
Cleanup method order: initialize first
Cleanup method order: type after initialize
Cleanup method order: dst_adjust? before builders
Cleanup method order: validate before builders