Merge pull request sass#3156 from mgreter/feature/harden-endless-extend

Fix extend edge case going endlessly

Merge pull request sass#3090 from mgreter/bugfix/fuzzy-crashes

Fix some null pointer access crashes

Merge pull request sass#3027 from mgreter/bugfix/misc-segfaults

Fix a few segfaults

Merge pull request sass#2997 from mgreter/bugfix/2884-attribute-selec…

…tor-equality

Fix attribute selector equality (include modifier)

Merge pull request sass#2909 from glebm/ptr-comparison

Add comparison operators for SharedImpl, fix bugs

Delete extconf.rb

This file is unused, the Ruby gem is at sass/sassc-ruby

Update plugin test script to use precision 5

Revert "Upgrade sass2scss to version 1.1.2"

This reverts commit ca89d73.

This bump caused some regressions that are preventing implementors
from upgrading.

See sass#2637 sass#2638

Mentioned SharpScss and LibSassHost in implementations.md

Merge pull request sass#2586 from mgreter/feature/backtraces

Implement more detailed backtraces