Add gtest 1.7.0-rc1
Initial add
Whitespace fixes
Ignore .xccheckout
Expand documentation
Switch to XCTest
Update shared scheme to use XCTest bundle
Support test filtering within Xcode

This fixes Google tests running when test execution was limited to a
different XCTest suite or case within Xcode. Rather than specifying a
test scope of only the suite/case to run Xcode specifies an inverse
filter excluding every test case except the selection. In order to
detect this the bundle defines a dummy testAll method and disables
running Google tests if this test case is excluded.
Update gtest to 1.7.0
Add iOS example
Fix signed conversion warning
Enable additional warnings
Add standard XCTestCase to test bundle

This demonstrates that standard Objective-C test cases can be used
alongside Google Test.
Add license header