Add ability to specify the :precision option about sassc-rails

[rastersysteme]

Would be great if #85 could be merged.

[glebm]

@phiggins For your workaround to work, you need to use prepend instead of include:

# config/initializers/sassc.rb
require 'sassc'

SassC::Engine.prepend(Module.new do
  def precision
    super || 10
  end
end)

Also due to missing parenthesis what you're actually calling is Engine.include(Module.new) do .. end which does nothing at all.

[rastersysteme]

This works as well:

# config/initializers/sassc.rb

if defined?(SassC)
  class SassC::Engine
    def precision
      8
    end
  end
end