Localization review according to regular Spanish and GC.com in Spanish (1st part)

This is the first part of my review for the Spanish localization. I have done three actions: add missed strings in Spanish from English XML; review existing strings to adapt them to "usual Spanish spoken in Spain" and used at GC.com in Spanish; and fix some little errors (misprints).

My main skills to do this: I'm Spanish from Spain and I play geocaching since 2006 (user: Nebur). Of course, I'm also a programmer in several languages :)

Modules reviewed in this proposal:
- Basics
- Caches
- Cache sizes
- Waypoints
- Logs
Merge pull request #2686 from nebursc/patch-2

Localization review according to regular Spanish and GC.com in Spanish (...