pick out compare packages function into separate exportable function;

filter out empty params on running `npm ls` command - problem inside vagrant;
add shell option to run `npm ls` correctly on Windows machines

Merge pull request #1 from velther/master

Moves npm process execution to `child_process.spawn`

some text and comment fixes

hashsum

fix bin

fix README

fix README

compitability with old node

fix console.log order