upgrade to SWT 4.3, including the switch of Mac builds to Cocoa API instead of Carbon
this requires rewrite of MacApplicationMenu to use the new Display.getSystemMenu()
MacApplicationMenu can now be compiled with any version of SWT, so move it to src and get rid of src-platform
fix InputDialogTest - it seems that SWT 4.3 setSelection(0, -1) doesn't work anymore
next version will likely be 3.3