rename 'reader' layout to 'webview'

this layout is for a generic webview, there's nothing about it specific
to the reader activity.

git-svn-id: https://android.svn.wordpress.org/trunk@957 a6565c4b-a94d-4d28-bb26-aa9e5ab542c0
refactor WebViewActivity

WebViewActivity is primarily used to display post and page previews, as
well as display the WordPress admin dashboard.  It looks like it
previously was also used for the WordPress.com reader?

This change refactors WebViewActivity into several classes to provide a
cleaner API, making it easier to add additional WebViews (coming soon),
and removes a significant chunk of duplicated and/or obsolete code.
There *should* be no user-visible changes here.

This change also starts putting Activities into the 'ui' package, as
things are getting a little crowded in org.wordpress.android.

git-svn-id: https://android.svn.wordpress.org/trunk@958 a6565c4b-a94d-4d28-bb26-aa9e5ab542c0
display open source licenses

new screen accessible via Settings > About.  Fixes #399

git-svn-id: https://android.svn.wordpress.org/trunk@959 a6565c4b-a94d-4d28-bb26-aa9e5ab542c0