Updated to support newest Gnome Terminal

The latest versions of Gnome Terminal store their settings and profiles
using the newer dconf system rather than gconf.  As such, the script
will now detect both the presence of dconf and the appropriate dconf
keys for Gnome Terminal.  When the dconf keys are not found, then it
will gracefully fall back to the old method using gconf.
Fix bad foreground color in gnome-terminal
Improve detection for new dconf usage and remove echoes
add Atom option for theme
Merge pull request #237 from Mattieuga/master

add Atom option for theme
Merge pull request #235 from yous/master

Fix typo, indentation, spacing and rename Putty to PuTTY
Merge pull request #208 from jreese/gnome-terminal

Updated to support newest Gnome Terminal