Remove unused page from stacked widget form, move duplicated code
into utility functions, reduce state variables and string comparisons
in RssFetcher, clean out includes. Give WelcomeModeTreeWidget
uniform row height.
* Use id() for methods returning a string used to represent
some type of object.
* Use displayName() for strings that are meant to be user
visible.
* Quieten some warnings while touching the files anyway.
* Move Factories to their products in the plugins where that
was not done before.
Reviewed-by: dt
This removes the all hard dependencies to and from welcome screen,
except the one to the core plugin. More in detail:
- Add IWelcomePage to add a tab to the welcome screen
- Move tabs in the modules where they belong
- Enables QHelpManager to open help fullscreen and contextually
- "Getting Started" moves to Qt4ProjectManager
- Projects & Sessions (aka "Develop") moves to ProjectExplorer
- "Community" remains in the welcome plugin for simplicity
