Fixes #90.

docs: update readme to install gulp-cli

add node_mirror and npm_mirror

Installation instructions

Updated readme.md to make sure to remove the existing npm install location

list available: show LTS and STABLE

load versions from https://nodejs.org/download/release/index.json

Skip the "Run cmd.exe" option on silent install.

Added a link to your Gitter page

Fixed for node v4

fix: 'install latest' works
fix: current version arch works

This is untested because the build chain isn't one I'm prepared to deal with.

fix issues related to showing the arch of installed node

Gtihub is a apparently a little picky about the syntax of this file name.

Add a local temp directory to prevent problems with cross-partition permissions. Closes #46.

download and unzip npm in a temp directory under the nvm root. fix issue
#46

Updated arch recognition for Windows 8.1