Added the beginnings of the XCTest implementation.

Added the new testing target and the scheme as well as some simple tests.
Merge remote-tracking branch 'origin/master' into Test-Integration
Added tests for adding a user, logging that user in, and logging that user out.
Added tests for ApigeeCompositeConfiguration class and updated the User test.
Added ApigeeMonitorSettings tests.
Updated ApigeeMonitorSettingsTests.
Merge pull request #81 from RobertWalsh/master

Added checks to make sure that we are not swizzling the NSURLConnections...
Added new tests and updated them along with the test structure in the project.
Added the ApigeeEntityResponse tests.
Merge pull request #84 from apigee/Test-Integration

Test integration
Added documentation for the various tests.
Merge pull request #85 from apigee/Test-Integration

Added documentation for tests classes.
added init with monitoring and urlTerms to ApigeeClient.h
fixed missing semicolon
Merge pull request #86 from apigee/urlTerms-fix

added init with monitoring and urlTerms to ApigeeClient.h