Improve SpellsPanel button descriptions

[collinsmith]

SpellsPanel button descriptions were thrown together and need to be gone over to make sure they align with the original game better. I've attached screenshots of examples of descriptions that need to be fixed. Three areas that I think need to be improved:

• Fixing the format strings so that they show the correct precision 4.333333 -> 4.3
• Time durations needs to be to converted into seconds
• Fixing layout where appropriate (some spells have fixed mana cost and don't show this in their level descriptions)
• Fixing errors in formatting (some descs only use part of the formula and cut off when the desc string is empty)
• Skills with sLvl == 0 should have white text printed as red

[collinsmith]

This appears to be a duplicate of #17