Add language identifiers to README.md code blocks
Add language identifiers to README.md code blocks

Add language identifiers to code blocks in README.md to make example code more readable on project homepage.
mac-cain13/CoreDataKit,tomlokhorst/CoreDataKit,tomasharkema/CoreDataKit,mac-cain13/CoreDataKit,tomasharkema/CoreDataKit,tomlokhorst/CoreDataKit