Some build 1503 bugs

Some 0.9.4 RC (build 1503) bugs
Platform: Windows XP

This is from my first test run using MuseScore, please excuse me if I'm duplicating known issues.

* Hairpins over system breaks are wrong. The continuation should start again where the music starts again (after the time sig gap). Look at Golliwogg's Cakewalk, meas 87-88. (The problem can be manually edited to look right.)

* When a note is cross-moved (Ctrl+Shift+Arrow) to another staff, a connected slur is reshaped as if the note still is at the original staff.

* HBox/VBox Properties (the margins) don't seem to do anything?

* "Add Less/More Stretch" are not recorded to the Undo list.

* "Staff Properites" and "Measure Properies" aren't recorded to the Undo list.

* When a measure is hidden (through "Measure Properties"), slures, hairpins and dynamics are still displayed.

* When a staff is displayed in small size (through "Staff Properties"), time sigs are still displayed in full size.

* In the wtc1fuga5 sample, there are lots of really wrong high beams in multi-voice measures. For example measures 13, 20, 21.

* Brackets can be resized vertically, but the resize cannot be preserved?

* Adding brackets (dragging a new bracket to a staff) aren't recored to the Undo list.

* Slurs and ties don't seem to use the same horizontal logic over system breaks. Problem displayed in meas 88 of the Golliwogg sample.

* Slurs and ties over system breaks goes exactly to the barline end of the first system, which isn't consistent with usual music layout. Usually, these elements stops with a small gap before the system end barline.

* When the palette is hidden and then redisplayed (pressing F9 twice), it resizes to occupy half the horizontal screen estate.