Fix reported file path to actual loaded file-name
Implement @debug statement analog to @warn statement
Improves @warn and @debug message to match ruby sass

Moved static get_cwd function to Sass::File namespace
Merge pull request #755 from mgreter/feature/debug-statement

Implement @debug statement
str-slice and str-insert should normalise quote to double quotes
str-slice with $end-at: 0 should never return a value
Merge pull request #762 from xzyfer/fix/str-slice-end-at-0

`str-slice` with `$end-at: `0 should never return a value
Merge pull request #764 from xzyfer/fix/normalise-str-function-quotes

str-slice and str-insert should normalise quote to double quotes
Correctly parse default and global flags in assignments
Merge pull request #765 from xzyfer/fix/asignment-parsing-too-strict

Correctly parse !default and !global flags in assignments
Guarded assignments should override null values
Merge pull request #766 from xzyfer/fix/guarded-assigments-override-null

Guarded assignments should override null values
Error when instantiating a map with duplicate keys
Merge pull request #768 from xzyfer/fix/error-on-duplicate-map-keys

Error when instantiating a map with duplicate keys
Don't output empty blocks
Hydrate division operands when it makes sense
Merge pull request #769 from xzyfer/fix/dont-output-empty-declarations

Don't output empty blocks
Merge pull request #770 from xzyfer/fix/hydrate-division-operands

Hydrate division operands when it makes sense
Improve static value look ahead parsing
Consume all the available semicolons