fpg_edit: refactored out the TextColor change due to negative/positive values.
fpg_edit: refactored out the TextColor change due to negative/positive values.

This allows use to reuse this bit of code without affecting the internal
FText values - as is caused by SetShowThousand in FormatEdit().

wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI,wkitty42/fpGUI