Dispatches callback to uv_default_loop.

Also fixes the issue with destination path
being resolved w.r.t input, without accounting
for it being already absolute.

For CLI format as JSON with indent = 2.

Credit goes to @mgreter.

This code is ported from @mgreter's fork.

Install: Removes excessive dependencies

CI: Use env.SKIP_SASS_BINARY_DOWNLOAD_FOR_CI

Fixes #537.

Change `--output` to be a directory

This makes it easier to watch a lot of files for changes and compile them to a
desired directory rather than writing them in `process.cwd()`.

Cleanup tests

add environment variable to force a build

this can be used to workaround #517

Added test for an issue found in the output of stats.includedFiles

Apply correct cflags to source files

Using -std=c++0x is sufficient to compile libsass

Libsass: Submodule now points to sass/libsass

Add test for watched files rendering

Set `options.src` to render the changed file when watching

Add test for watching files