DATACOUCH-142 - Update documentation and provide migration cheatsheet.

The documentation has been updated to reflect the changes in the new Spring Data Couchbase 2.0.

A simple list of major changes to take into account when migrating from 1.x to 2.x has been added.

README.md has also been updated.

src/main/java/org/springframework/data/couchbase/config/AbstractCouchbaseConfiguration.java

@@ -202,7 +202,7 @@ public abstract class AbstractCouchbaseConfiguration {
   /**
    * Scans the mapping base package for classes annotated with {@link Document}.
    *
-   * @throws ClassNotFoundException if intial entity sets could not be loaded.
+   * @throws ClassNotFoundException if initial entity sets could not be loaded.
    */
   protected Set<Class<?>> getInitialEntitySet() throws ClassNotFoundException {
     String basePackage = getMappingBasePackage();