Upgrade libsass to latest master SHA hash

Tests didn't run on my local machine, however when
checking with the untouched node-sass they didn't
run either with the same errors.

For reference, these were the errors:

```
npm test

> node-sass@0.8.6 pretest ~/node-sass-orig
> node scripts/lint


> node-sass@0.8.6 test ~/node-sass-orig
> node scripts/test
  4 Upgrade libsass to latest master SHA hash


  ․․․․․․․․․․․․․․․․

  1 passing (334ms)
  15 failing

  1) cli should compile sample.scss as sample.css:
     Uncaught AssertionError: {"killed":false,"code":8,"signal":null} == null
      at ~/node-sass-orig/test/cli.js:43:14
      at ChildProcess.exithandler (child_process.js:651:7)
      at ChildProcess.EventEmitter.emit (events.js:98:17)
      at maybeClose (child_process.js:753:16)
      at Socket.<anonymous> (child_process.js:966:11)
      at Socket.EventEmitter.emit (events.js:95:17)
      at Pipe.close (net.js:465:12)

  2) cli should compile sample.scss to ../out.css:
     Uncaught AssertionError: {"killed":false,"code":8,"signal":null} == null
      at ~/node-sass-orig/test/cli.js:58:14
      at ChildProcess.exithandler (child_process.js:651:7)
      at ChildProcess.EventEmitter.emit (events.js:98:17)
      at maybeClose (child_process.js:753:16)
      at Socket.<anonymous> (child_process.js:966:11)
      at Socket.EventEmitter.emit (events.js:95:17)
      at Pipe.close (net.js:465:12)

  3) cli should compile with --include-path option:
     Uncaught TypeError: undefined is not a function


  4) cli should compile with the --output-style:
     Uncaught TypeError: undefined is not a function


  5) cli should compile with the --source-comments option:
     Uncaught TypeError: undefined is not a function


  6) cli should compile with the --image-path option:
     Uncaught TypeError: undefined is not a function


  7) cli should write the output to the file specified with the --output option:
     Uncaught TypeError: undefined is not a function


  8) cli should compile with the --source-map option:
     Uncaught TypeError: undefined is not a function


  9) cli should compile with the --source-map option with specific filename:
     Uncaught TypeError: undefined is not a function


  10) cli should compile a sourceMap if --source-comments="map", but the --source-map option is excluded:
     Uncaught TypeError: undefined is not a function


  11) compile file with source comments should compile with render and comment outputs:
     Uncaught TypeError: undefined is not a function


  12) compile source maps should compile file with source map URL:
     Uncaught TypeError: undefined is not a function


  13) stats using renderSync() and file-context "before all" hook:
     Error: the string "error reading file "[object Object]"
" was thrown, throw an Error :)
      at Runner.fail (~/node-sass-orig/node_modules/mocha/lib/runner.js:197:11)
      at Runner.failHook (~/node-sass-orig/node_modules/mocha/lib/runner.js:225:8)
      at ~/node-sass-orig/node_modules/mocha/lib/runner.js:264:14
      at done (~/node-sass-orig/node_modules/mocha/lib/runnable.js:185:5)
      at Hook.Runnable.run (~/node-sass-orig/node_modules/mocha/lib/runnable.js:219:5)
      at next (~/node-sass-orig/node_modules/mocha/lib/runner.js:259:10)
      at Object._onImmediate (~/node-sass-orig/node_modules/mocha/lib/runner.js:276:5)
      at processImmediate [as _immediateCallback] (timers.js:336:15)

  14) stats using renderSync() and data-context "before all" hook:
     Error: the string "source string:1: error: invalid top-level expression
" was thrown, throw an Error :)
      at Runner.fail (~/node-sass-orig/node_modules/mocha/lib/runner.js:197:11)
      at Runner.failHook (~/node-sass-orig/node_modules/mocha/lib/runner.js:225:8)
      at ~/node-sass-orig/node_modules/mocha/lib/runner.js:264:14
      at done (~/node-sass-orig/node_modules/mocha/lib/runnable.js:185:5)
      at Hook.Runnable.run (~/node-sass-orig/node_modules/mocha/lib/runnable.js:219:5)
      at next (~/node-sass-orig/node_modules/mocha/lib/runner.js:259:10)
      at Object._onImmediate (~/node-sass-orig/node_modules/mocha/lib/runner.js:276:5)
      at processImmediate [as _immediateCallback] (timers.js:336:15)

  15) stats using render() and file-context "before all" hook:
     Uncaught TypeError: undefined is not a function
```