#705 Move column fails in some circumstances

[Javier Paniza]

To reproduce: Take the Invoice module of OpenXavaTest and try to move the Paid property to the third position (just after number). It fails with:

java.lang.ArrayIndexOutOfBoundsException: -1
at java.util.ArrayList.remove(ArrayList.java:390)
at org.openxava.util.XCollections.move(XCollections.java:104)
at org.openxava.util.XArrays.move(XArrays.java:60)
at org.openxava.tab.Tab.move(Tab.java:2027)
at org.openxava.tab.Tab.moveProperty(Tab.java:2018)
at org.openxava.web.dwr.Tab.moveProperty(Tab.java:43)