Reorganize the different overviews in the Qt documentation

We need to go over all overviews in the documentation and make sure they connect and cover all of Qt.

• Getting started - new
• Installation & first steps - edited
• How to learn Qt - old setup
• Tutorials - old setup
• Examples - old setup
• Whats new in Qt 4.7 - old setup

• Class index - old setup
• Function index - old setup
• Modules - old setup
• Namespaces - old setup
• Global Declarations - old setup

• Programming with Qt - new
• Qt Architecture - edited
• Cross-platform & Platform-specific Development - edited/new based on the two
• Qt & standard technologies - edited
• Qt How-to's & best practices - old

• Qt Quick - edited
• Introduction to QML - edited
• QML Elements - edited
• UI components - edited
• Qt & GUI design - new

• Qt Creator - old setup
• Qt Designer - old setup
• Qt Linguist - old setup
• Qt Assistant - old setup
• Integration and add-ins - old setup
• Virtual Framebuffer - old setup