Target class converted to PodTarget and SpecTarget representing Pod 
integration targets and podspec targets.
TargetInstaller converted to PodTargetInstaller and 
SpecTargetInstaller to handle variations in installing Pod targets 
and spec targets.
XCConfig generator converted to PodXCConfig, PublicSpecXCCconfig and 
PrivateSpecXCConfig classes to handle generating the different 
xcconfig files.
Requires Xcodeproj file changes to support namespaced xcconfig files.

* master: (34 commits)
  [SpecHelper] Use coveralls head which fixes issues with colored
  [Integration] Update fixtures for Generator::CopyResourcesScript
  [Generator::CopyResourcesScript] Clean-up
  Update CHANGELOG.md
  Update CHANGELOG
  [Gemspec] Include sandbox-pod
  [SanboxBin] Include /usr/libexec
  [Sandbox] Reading from paths that contain executables should be safe.
  [Sandbox] Remove doc generation related rules and allow for more prefixes. (E.g. MacPorts.)
  [Search] Show all command options.
  [Travis] No need to install Mercurial anymore 2
  [Travis] No need to install Mercurial anymore
  [Complete] Fix copy resources script for iOS < 6 and OS X < 10.8
  added issue link to the fix
  updated changelog for inhibit_warnings fix
  [Changelog]
  [Specs] Refine output
  [Specs] Facelift inspired to xctool
  [Changelog]
  [Integration] Use aggressive cache
  ...

Conflicts:
	lib/cocoapods/installer/target_installer.rb
	spec/integration/install_external_source/after/Pods/Pods-resources.sh
	spec/integration/install_local_source/after/Pods/Pods-resources.sh

See #1030

See #1030

Conflicts:
	Rakefile

Related #1037

The xcodebuild -target <target> invocation does not support implicit 
dependencies.  Therefor building the Pods integration library fails 
because none of the spec libraries are built.  Building a scheme 
results in proper implicit dependency resolution, but there are no 
schemes created in the integration tests.  Just walk the list of 
spec libraries and manually build all dependencies before building 
the Pod integration library.

The target integrator is only run when libraries are being integrated 
with user projects.  The Pods integration library needs to be 
updated, linked with the spec libraries, regardless of user 
project integration.

Remove the following flag from the script to avoid crashes

ibtool:

--reference-external-strings-file
              When combined with the --compile option, this flag indicates that the files in the Base.lproj locale  folder  should  be
              compiled  to reference the matching external strings files found in the other locales when loaded. Available on 10.8 and
              later.

* master:
  [Rakefile] Perform setup on for integration only if needed 2
  [Rakefile] Don't set the git user as not needed anymore
  [Rakefile] Perform setup on for integration only if needed.
  [Doc] Make clear that an error occurred in a pre/post hook.

This skips the unneeded update.