[Integration] Fix integration while project is open

While a user project is open and we delete/change the xcconfig files which
the user project references. It causes any subsequent builds to fail
until the project is closed/re-opened, or the project file is touched.

This commit touches the file if we do not need to save it, thus causing
Xcode to reload it.

Closes #2627
Closes #2665
[Gemspec] Bump to Xcodeproj 0.19.4
[Gemspec] Bump to cocoapods-trunk 0.3.1
Indentation! Indentation! Indentation!

Indentation! Indentation! Indentation! Indentation! Indentation!
[ErrorReport] Include git information in stack

Closes https://github.com/CocoaPods/CocoaPods/issues/2678.
[LICENSE] Time. It still passes.
Added a mising backtick in xcconfig_integrator warning message
fixes crash when using file URLs https://github.com/CocoaPods/CocoaPods/issues/2683
Merge pull request #2686 from nemesis/add-a-missing-backtick

Added a mising backtick in xcconfig_integrator warning message
added spaces in CHANGELOG and reversed conditional in name_for_url method
Merge pull request #2687 from Kurry/2683-crash-when-using-file-url

fixes crash when using file URLs.
Fixes usage of pods in static libraries with Xcode 6.

Fixes #2666.
Merge pull request #2676 from CocoaPods/issue/2666

Fixes an issue when using pods in static library targets
Update spec integration fixtures
[Resources] Fix when Xcode is installed with space in path

Fixes #2684
Update spec integration fixtures
[travis] Simplify configuration and use bundler cache
[Spec] Fix stubbing removed method resulting in test taking 10s
[Spec] Correctly stub the sources used for search

Before, we was stubbing something which wasn't called and thus searching
the whole master repository. This change shaves 20 seconds off the
testing time.
[Resources] Fix issue installing to target without resources

Fixes #2083