True 3.0!

(copied from 3-beta release notes…)

• Added describe and it mixins,
  as alias for test-module and test respectively.
• Added $inspect argument to assert-equal and assert-unequal mixins,
  for comparing inspect($assert) == inspect($expected)
  instead of $assert == $expected.
  This helps with several of the equality edge-cases listed below
  (rounding and units).
• BREAKING: No more Ruby gem or Ruby CLI
• BREAKING: No more bower package
• BREAKING: Removes special-handling of equality,
  in favor of allowing Sass to determine the best comparisons.
  There are a few edge-cases to be aware of:
  • In some versions of Sass,
    manipulated numbers and colors are compared without rounding,
    so 1/3 != 0.333333 and lighten(#246, 15%) != #356a9f.
    Use the $inspect argument to compare rounded output values.
  • In all versions of Sass,
    unitless numbers are considered comparable to all units,
    so 1 == 1x where x represents any unit.
    Use the $inspect argument to compare output values with units.
  • Lists compare both values and delimiter,
    so (one two three) != (one, two, three).
    This can be particularly confusing for single-item lists,
    which still have a delimiter assigned,
    even though it is not used.