Vanquish

This release backports bugfixes and improvements from master to libsass 3.4.

Release was tested with valgrind against all spec-tests to be free of (known) leaks.

Fixes

• Fix math with multiple units (@mgreter, #2549)
• Make error indicator Unicode aware (@mgreter, #2319)
• Make sourcemaps fully Unicode aware (@mgreter, #2543)
• Fix parser state column following static values (@mgreter, #2312)
• Fix memory leak of custom functions signature (@DerPapst, #2553)
• Adding the missing scope identifier std:: (@phg1024, #2545)
• Fix fall-trough warning in latest gnu gcc (@mgreter, #2547)
• Tweak warning message format (@xzyfer, #2536)
• Fix msvc compiler warning (@mgreter, #2547)