Use a XML pull parser to parse .loc files

Parsing XML with regular expressions is bad.
fix #4441: wrong distance in lists for caches with modified coordinates

The coordinates used to get the cache location were taken from the .loc
data for premium members of geocaching.com and basic members with
captcha enabled. This has been changed to not use the data from the .loc
data when precise location is already available from the database or the
cache.
Remove redundant initializer
Add a Geocache.getGeocodes helper for a common pattern
Load caches from database in parallel from .loc file fetching