Allow failures for node v0.11 on travis

Promoted @am11 to project lead

Added travis => gitter webhook

Binary: Removes v8 version from the dir name

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

0.6.4 doesn't include pre-built binaries which makes it incompatible with systems
without Python installed.

Fixes #518