More constructors

[zaccret]

In the continuation of the javabeans convention (getters/setters instead of public properties), I think that constructors with often-used fields would be appreciated by gxt users.
For example :
- Container and all its subclasses could have a Container(Layout) constructor
- ContentPanel could have a ContentPanel(Layout,String) constructor and a ContentPanel(String) constructor for layout and heading text
- TextToolItem could have a TextToolItem(String,Menu) constructor for item text and menu.

[jgindin]

+1

[gslender]

+1

[rdrever]

+1

[zaccret]

Darell, can we get it for the next release :) ?