add tests for not expressions
Moved extend test 190 out of todo, added test of @extend output.
Removed basic-extend-tests, as they are duplicated in extend-tests.
add tests for CSS native filter functions

Add tests to verify that attempts to use native CSS filter functions,
like `grayscale(20%)`, are properly passed through to CSS unchanged,
rather than interpreted as the Sass function `grayscale` that operates
on colors.

Fixes compatibility with Ruby Sass.
Merge remote-tracking branch 'michaek/feature/remove-basic-extend-tests'
Merge remote-tracking branch 'michaek/feature/placeholder-grouped-selector'

Conflicts:
	spec/extend-tests/190_test_semi_placeholder_selector/input.scss
Moved passing extend tests out of todo folder.
Added placeholder-with-media test case.
Removed spec/scss-old, as diff -r showed no changes from spec/scss.
Removed spec/todo/scss-old.
Disabled tests that cause fatal errors in Ruby Sass.

Set explicit Sass version in Gemfile.
Added note to Readme about renaming test cases.
Disabled tests of functions not defined in Sass 3.2.
Made test name more obviously reflect directory structure.
Output Sass version from executable before running tests.
Add test for sass 3.3 maps api
Merge pull request #14 from nsams/test-not-expr

add tests for not expressions
Merge pull request #35 from benesch/filter-effects-functions

add tests for CSS native filter functions
Merge pull request #44 from xzyfer/feat/maps

Add test for sass 3.3 map functions
Merge pull request #33 from DealerDotCom/feature/placeholder-grouped-selector

Moved extend test 190 out of todo, added test of @extend output.
Merge pull request #34 from DealerDotCom/feature/remove-basic-extend-tests

Removed basic-extend-tests, as they are duplicated in extend-tests.