SDL2 - Battle Mode Font Update

Hi,

During the SDL2 font update, the HP and SP numerical text became off center in battle mode.  I do not know why or have a reason as to why this happened nor why other text elements were not affected.  However, this update changes their offsets to re-center them.

In addition, I also added some minor aesthetic updates to the UI in battle mode.  For example, a character with full SP would cause the blue, SP bar to overextended the yellow, selection bar to right by a couple pixels.  I tried to fix these kinds of issues.

Thanks. 
The assert is weirdly located, IMO.