These files are automatically generated by Xcode and maintain
information regarding source control. Xcode is typically used
in Objective-C and Swift projects, so add these to the ignored files for
these platforms.

some details based on #1221

This updates the link provided to the CocoaPods documentation regarding whether the Pods directory should be ignored or not.

removing this aditional white space avoid a mistake for beginners developers ignore the pod directory, because is confusing to note when they remove the '#' character and git still is tracking the pod dir.

This got changed recently.

xcuserstate files are generated from within Xcode and saved in your project bundle to remember your last opened file, the open state of any group folders, open tabs, and any other user setting your project might need to remember

We shouldn't be ignoring these, it's down to the user and we shouldn't enforce them to ignore the `Pods/` directory

http://guides.cocoapods.org/using/using-cocoapods.html#should-i-ignore-the-pods-directory-in-source-control?

The pattern `*.xccheckout` is already ignored on line 15.

This is a file that Xcode 5 uses for version control, doesn't need to be checked in. Also see http://stackoverflow.com/a/18448100/1877078

Per discussion in #148.

Reverted a change that was causing build directories at the root folder to show up in git.  If you need to ignore subdirectories the leading slash needs to be omitted.

Workspaces are real documents that can be opened, just like `xcodeproj`
documents. These documents are also generated/used by CocoaPods to
configure a project’s dependencies. For these reasons, there does not
seem a good reason to ignore these any longer.

DerivedData is the "build/" Folder that *might* be in your Project's folder if you use the default Xcode 4 settings.