Display math objects should use Visual Line select

[jcommelin]

Most people write their display math like this:

\[
    a^2 + b^2 = c^2
\]

Hence, I think it would be totally naturally to use Visual Line (Shift-V) select when operating on these text objects. (Maybe the plugin CountJump can help here.)

[gibiansky]

I added a variable for this. If you set

let g:latex_select_math_lines = 1

before loading the plugin it will use V instead for square braces.

Feel free to reopen any issues if things aren't fixed for you after updating.