Change QDoc's output to use the new QML terminologies

Summary of terminology:

1)Qt Quick: QML (the language + engine + global objects) + Qt Quick Elements (import QtQuick 2.0)+ tools (Creator)

2)type: a QML type or a basic type (the primitives such as bool, int, etc.)

3)QML type: the thing you declare. "Item {}" is a type. but "Item element" is appropriate to associate it to the Qt Quick Elements.

4)element: the types in the Qt Quick Elements imported using QtQuick 2.0. They implement UI and application features.

5)ui component: QML types that are in the Qt Quick Components or are a unit of the user interface

6)component: built using types and loaded into the engine or runtime. Also for UI components. "Button component"

7)engine: the QML engine implemented using Qt C++ (QmlEngine and related classes)

8)item: any type that is built using Item or types based from Item element. Also appropriate when referring to things in a list or menu (list items)

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QDoc's changes:
1) \since command's output to "This type was introduced..."
2) maybe the HTML file name output? There is a prefix to set in the qdocconf...but I don't know how far the change should be.
3) Maybe add an argument to \qmlclass to allow custom names? "\qmlclass <type> 'My <Type> Component'"