[Gitbro-develop] add a new text widget

[guosong z. <bil...@gm...>]

Now, I add a new text widget with a vertical scrollbar and fix a few bugs
last time, for example,
1. the GUI can display full screen
2. use pack geometry management instead of grid.  Maybe grid method is
better than pack, but I can
 not operate it well to make GUI full-screen display.
3. a little trick with entry widget, when click 'search' button, then the
entry widget will appear in the
 right side of the 'search' button. It is also stupid, if click 'search'
again, the entry will appear again.
 So, I need to fix the bug. Though this feature is not necessary, but I
think it is interesting so I do not
 want to cancel it. But those are all decorations now.
4. the file button can work now. If click it, a file named '11.txt' in the
current directory will be displayed
 in the right side text widget. This also can be rewritten to be more
general. It is just a test in order to
 know how to read a file in  text widget.
5. There is no necessary to add a horizontal scrollbar in text widget,
because a option wrap with default
 value WORD forbids the functionality of the horizontal scrollbar, with the
default value a line can be split
 by word when it reach the boundary of the text widget. Only configure wrap
with NONE, the horizontal scrollbar
 will take effect.