Added chrome.rc to fix Google Chrome window borders.

Using Mint-X, the Google-Chrome window borders incorrectly picked up the
theme_selected_bg_color, which makes them stand harshly against the
window borders. This customization file corrects this to display as a
matte-grey.
Adds chrome.rc to the include directives in gtkrc.
Merge pull request #21 from wrouesnel/chrome-fixes

Google chrome fixes