use explicit side when checking for diseases in body_window
use get_HP_Bar in body_window
fix memory leak in body_window:

don't leave the function with return before deleting the created window!
disallow selecting body parts that are not shown.
Protect loading submaps with a try-catch-block.

In case the maps are invalid/wrong/whatever. At least don't crash.
Merge branch 'handle-invalid-maps' of https://github.com/BevapDin/Cataclysm-DDA into merge