[Feature Request] Share a scheme created when duplicating a target. #28

Hi.

I happen to use XcodeEditor, but not directly. I am using Calabash for iOS for automation tests, and calabash is using XcodeEditor. They have calabash-ios setup command, which does the following

• Duplicate an existing target (say "MyTarget") and name it using "-cal" suffix, say "MyTarget-cal"
• Add calabash.framework to newly created target
• Modify "Other Linker Flags" for "MyTarget-cal"
  All that using XcodeEditor.

When new target is created, a new scheme appears in the Xcode as well, in my case it's "MyTarget-cal" scheme.

So, the problem is that newly created scheme is not shared.
If I go to "Manage Schemes" Xcode menu, the "MyTarget-cal" scheme will not have checkmark in "Shared" column, even if the original "MyTarget" scheme had it.

Why that matters?
It is not a problem when building from Xcode and when using xcodebuild from command line on dev machine.
But that becomes a real problem when trying to build from CI environment, such as Bamboo or Jenkins.
It's a known issue, Bamboo and Jenkins run their shell scripts in a specific environment, under some special user. So when Bamboo runs xcodebuild -project MyProject.xcodeproj -scheme MyTarget-cal the xcodebuild will complain that the project does not have "MyTarget-cal" scheme. To put it another way, Bamboo and Jenkins can't "see" scheme unless it's shared. That's why having a shared scheme is important for CI builds.

Most of Xcode projects can be build using only configuration, target and sdk options, but if it's an Xcode workspace with lot's of libraries, sub-projects and custom frameworks, building using -scheme option is the only way to build it from command line properly.

I've done some research around the shared schemes.
If the scheme is shared in Xcode, then it will appear in MyProject.xcodeproj/xcsharedata/xcschemes, for each scheme there will be a .xcscheme file, like "MyTarget.xcscheme", "MyTarget-cal.xcscheme".
But that folder and its contents are created only when the project is opened in Xcode, looks like Xcode generates those folders and files.
When the whole thing is done on CI box, none of those folders and files will be created.

The only place I can find mention of "MyTarget-cal" target and scheme is in "MyProject.xcodeproj/project.pbxproj" file.
I assume there's a way to extract information about "MyTarget-cal" scheme from pbxproj file and create "MyTarget-cal.xcscheme" and put it under "xcshareddata/xcschemes", at least Xcode does that somehow.