Adjust and improve Wiki pages about flexibleadapter

[davideas]

Added structure description about how this library is designed. Direct link: Library structure.
Added a side navigable menu.

[davideas]

Added a new Wiki page about how to implement sections with sticky headers and expandable sections. Direct link: Headers and Sections.

[davideas]

Added new Wiki page about Setting Up and how to initialize the adapter.

[choxnox]

Documentation definitely needs improvement because I've just wasted the whole day trying to figure out why my initial list with headers isn't working and throwing ClassCastException only to find out it's because I was using the same layout resource for both items and headers (for e.g. android.R.layout.simple_list_item_1).

Not only that but it appears getLayoutRes function is internally called within adapter which means it's also mandatory to implement it and nothing of this is mentioned in the documentation.

[davideas]

@choxnox, I'm sorry if you got lost in the implementation, the page Setting Up, actually shows the 2 ways to implement the binding (normal way or with item interfaces). Also, you could read the comments of every single methods (to override) of the Adapter and of the item interfaces.

All the rest of the pages will come, as soon as I resolve some (life) issues...

[davideas]

Added new Wiki page about Drag&Drop and Swipe.

[davideas]

Wiki pages tutorial has been completely reviewed
In the coming weeks, more pages will be completed as well.

[davideas]

Added Demo App Wiki page.

[davideas]

Reviewed Setting Up and added Setting Up Advanced Wiki pages.

[davideas]

Added Scrollable Headers and Footers.

[davideas]

Added Payload & reviewed all existent pages.

[shymmq]

Load more upon a user request isn't really documented well. Should I call adapter.onLoadMore()? If yes, when? Will the items be added automatically or do I have to add them manually? Also, there is no example on this topic in the demo app, only automatic loading.

[davideas]

@shymmq, that part is indicative (without example yet), but the logic steps are described. I added another point to complete the loading once the items are received.

onLoadMore() is for automatic loading, so you don't have to call it. The items are loaded when user clicks on the button that you add in the layout of the progress bar. The callback of that remote call will invoke onLoadMoreComplete(newItems).

[davideas]

With RC2 release many pages have been reviewed already, all the remaining will be updated soon.