Use the last stable nvm, not the master version

The nvm version from master is unsupported and may be broken. Using a tag
is advised.

CI: Build for node 5.x

Added a test for #1219

The previous file should be the absolute path, not the string used to import it.

fix to allow node-sass to pipe content with embedded sourcemap to other tools

making sass logo size more appropriate

Bump LibSass to 3.3.1

Bump LibSass to 3.3.0

Bump LibSass to 3.3.0-beta3

Fix a typo "repsonse" to "response".

Fixed typo "Sepcial" to "Special" in "// only one of them is required, see section Special Behaviours" (line 319 in examples section) in README.md.

Add --follow option to the CLI

Use sass binary url from .npmrc if available

For pull requests and pushes to master just build 32-bit binaries
and do not store artifacts.

Whenever a tag is pushed to the "release" branch - produce
full set of 32-bit and 64-bit binaries, create a GitHub
release (if does not exist already) and attach the binaries
to the release.

Issue open:

http://bit.ly/twoBuilds

 AppVeyor starts two builds in response to the "new commit"
 and "new tag" events.

Import libsass 3.3 code

- New source layout
- New header names for #include
- No need for exception handling in pure C code