Fix build issue.Fix node_mirror, npm_mirror not work issue.Add cleanup work when download is interrupted by user.

Fixes #245.

Update README.md

- Added badges for issue count and repo stars
- Updated screenshots

Replacing prefix only if is in head of line.

Tested using below
nvm proxy http://username:password@cchproxy:8080 & nvm proxy

nvm proxy username:password@cchproxy:8080 & nvm proxy
nvm proxy http://proxy:10080 & nvm proxy
nvm proxy http://proxy:proxy@proxy:10080 & nvm proxy
nvm proxy proxy:10080 & nvm proxy

concerning  https://github.com/coreybutler/nvm-windows/issues/186

Update README.md

Fix "nvm use" swapping node32 and node64 even when not need (issue #134)

Show message when requesting a 64-bit version that is only installed as
32-bit. Mirroring what is shown when requesting a 32-bit version that is
only installed as 64-bit.

Removed the link to nvmw project because it is no longer maintained.

Update README URLs based on HTTP redirects

Fixes #90.

docs: update readme to install gulp-cli