adds quick improvements

we don't have to strip strings in order to check for line presence
stops removing empty lines from fstab
removes extra newline chars
fixes check for line addition

using #grep when then have to ask the result if it's not #empty?
using #any? makes sense, but we should still use a regex instead of
performing a string equality test
adds newline at the end of addition
makes array join explicit
reverts back to orig addition comparison
Merge pull request #11 from orgsync/improve-fstab-layout

A few more tweaks to the /etc/fstab file