.osx: Disable Spotlight suggestions from Safari

Safari has a “Spotlight Suggestions” setting that, if left enabled, will send a copy of all search queries to Apple.

Closes #455.
.osx: Add Yosemite’s search results for Spotlight

Yosemite introduces new Spotlight search results, and if you don’t add it to `defaults write com.apple.spotlight orderedItems` it will be removed from the System Preferences → Spotlight → Search Results` list with no way to re-enable them through the System Preferences panel.

Closes #456.
commiting for merge
Add .gdbinit
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