[1.1.20] - Fix several bugs from the last refactoring.

- isValid() was always returning false for Object-type variables,
because
isNaN() confusingly returns true for objects.
- Typo in the battle standard code kept the party controls from being
displayed.
- Typo in the party() code kept you from being able to unparty cavalry
if
there were no soldiers in the party.
- Simpify the Number type conversion in getCustomNumber().
- Refactor the healer code into its own function.
Merge branch 'master' of https://github.com/ZZJHONS/CivClicker

Conflicts:
	images/Thumbs.db