[FIX] Pre-defined margin classes: use extra class to reset width
In the initial implementation of the margin classes we incorporated
'width: auto !important' for all css classes that contianed a horizontal
margin. 
This would destroy any non 100% width that a control may have.
Therefore I added an extra class 'sapUiForceWidthAuto' which sets
'width: auto !important' and which may be added by the application
developer as needed

Change-Id: I67cdc0b32647e8d1c76e4c6cd1128b9cf26a95ec
Merge "[FIX] Pre-defined margin classes: use extra class to reset width In the initial implementation of the margin classes we incorporated 'width: auto !important' for all css classes that contianed a horizontal margin.  This would destroy any non 100% width that a control may have. Therefore I added an extra class 'sapUiForceWidthAuto' which sets 'width: auto !important' and which may be added by the application developer as needed"