Adds didUpdatePackages global to detect downloads.
Adds some temporary masks to gitignore.
Adds update suggestion to failed install commands.

The install proc checks the didUpdatePackages first to avoid infinite
recursion.
Adds -y/-n switches for non interactive operation.
Removes didUpdatePackages check without json file.
Merge branch 'pr_polite_install' of git://github.com/gradha/babel into gradha-pr_polite_install
Refactored code so that it doesn't use a global variable.