Fix invalid positioning when basket is scrolled

When basket got scrolled down or right itemAt(enent->screenPos()) method treats screenPos() as coordinates from the absolute topleft corner of the view not the scrolled one. So when basket is scrolled and user starts selecting text inside editor note dragging starts instead. This is fixed by taking into account scroll shift
compilation fix
Prevent drag & drop group of notes into itself
merge pull requests #5 and #6
Fix basket export and linking issues

Basket export: save full hierarchy to baskets.xml
Do not add .basket to archive: starting from KDE 4.0 hidden files are processed by addLocalDirectory
Made IconNames 'const char* const'
Fixed unit tests linkage problem. Due to build-time file generation we can only enable tests after make was run once