#17 created new Dialog to get the desired features.
#17 changed the size and format of the new dialog box
#17 added still missing strings
#17 the dialog is a singleton now
#17 modifed the behaviour, when the green arrow appears
#17 textfield is actualised in getInstance()
#17 put visualizePosition() and setTfCoordinatesTextToCenterOfCamera() on the right place in getInstance()
#17 added question mark image to dialog, moved arrow into cismap plugins images folder and changed layout of dialog
#17 removed double dialog.setVisible() and not usefull comments
#17 arrow is not shown immediately, when dialog is opened. visualizePosition() does not remove all stickynodes but only the arrow.
#17 increased lower inset of the dialog to 6
#17 use setVisibilty() of pMark only when necessary (in constructor)
#17 when the green arrow is visualized, only the old arrow is removed from the map. and not all sticky nodes
#17 when the position marker is visualized all children from the highlighting layer are removed. And all children from highlightinglayer are removed again.
Merge branch 'feature/17-positioning-with-optional-marker' into dev