Base ItemsBrowserFragment and ScItemsLoader added.
Added caching Item.HasChildren
Items browser in progress.
Merge branch 'dev' into items-browser

Conflicts:
	sitecore-api-android/sitecore-api-android.iml
	sitecore-api-android/src/net/sitecore/android/sdk/api/model/ScItem.java
Fixed parsing Item.HasChildren; GetItemsResponseParser renamed.
Added deleting cached items before new response received.
Various callbacks added.
Add ScItemsLoader ability to load fields.
Loading fields by ScItemsLoader finished.
Merge branch 'dev' into items-browser
Fixed ScApiSession -> ScApiSessionFactory
Removed ScApiSession initialization from ItemsBrowserFragment
Fixed calling new methods on old sdk.
More javadocs and useful methods.
Javadocs, code cleanup.
Added GRID style for ItemsBrowserFragment.
ItemsBrowserFragment.onInitialized added.
Fixed list item layout size; added ability to set root folder.
Ability to set root folder from layout.xml
Added ability to set header/footer view; callbacks updated.