Fix for TextBoxes not moving the text when caret needs to move

## Bug ##
If the caret moves out of the TextBox's range or adding characters that exceed the textbox's visible space, the text wouldn't move.

## Fix ##
Adds empty PostLayout() in TextBox class to avoid Label's PostLayout from being called. Otherwise the text's position will always be set to a fixed position defined by the alignment.

## Misc changes ##
- Removed extraneous semicolon in TextBox::MakeCaratVisible()
- Added newline in TextBox.cpp to avoid GNU compiler warnings