#25 Changes in "atlsplit.h" to reduce target file size

[ZhangBomin]

I've changed the CSplitterImpl's template
parameter "t_bVertical" to member
variable "m_bVertical". This can reduce the target file
size by about 4K bytes if a program uses both
horizontal splitter and vertical splitter. Don't forget that
one of the reasons programmers prefer WTL to MFC is
the code size.

The class's interface doesn't change much, and if a
program uses CSplitterWindow or CHorSplitterWindow
directly (that's don't have its own splitter class devired
from CSplitterImpl), it can even ignore these changes.

[ZhangBomin]

[Nenad Stefanovic]

Yes, this is a good idea. Breaking change, but worth it. I guess this was a case of going too far with templates :-)

This is now a BREAKING CHANGE - if you already have custom splitter (using CSplitterImpl or CSplitterWindowImpl), you'll need to change your code.

I also added new method: SetOrientaton(bool bVertical) which allows switching between vertical and horizontal splitter after splitter is already created.

Commit #499, atlsplit.h