Merge pull request #206 from mikeh/master

Unit test fix - delay before folder delete
Fix for MOBSDK-636 & MOBSDK-640. All sites fix from 1.5.x app has been integrated in the SDK and the site caching mechanism has been refactored.
Merge branch 'topic-MOBSDK-640'
Merge pull request #207 from gavincornwell/master

MOBSDK-636 & MOBSDK-640
Improvements to last commit following pull request review.
Merge pull request #208 from gavincornwell/master

Improvements to last commit following pull request review.
Refactoring: Converted to modern Objective-C syntax
Update unit test framework to XCTest
- Fixing static code analysis issues
Update unit test framework to XCTest
- Fixing static code analysis issues in sample apps
Objective-CMIS libraries updated to support 64-bit
Update unit test framework to XCTest
Code tidying: Removal of dead code and unused imports.
Code tidying: Fix typos throughout the SDK and Unit Tests
Code tidying: Simplifying if() statements and removing “== YES” and “== NO” statements
Code tidying: Fix variable casting. Fix error returns in several completion blocks
Additional updates to ObjectiveCMIS - typos and encoding fix