What is the "Qt Quick Compiler build tool"
I see the comparing table on the new download site and find "Qt Quick Compiler build tool" is not available in the free open source edition.The comment of this feature is "Compile dynamic UI files into your binary". As I know, qml files can be embeded into exe by adding as resource files into qrc file. Does it now mean that we can not compile qml as resource in free edition in the future?
No. it does not prevent you from using qrc.
Take a look on "Getting Started":http://doc.qt.digia.com/QtQuickCompiler/ it explains how qt quick compiler works.