Fixes in download and core.

 * Update status when downloading overview.
 * Refactor status resolving when downloading details.
 * Prevent `TypeError` when simulating GPS.
 * Remove useless whitespaces from `cachedownloader`.
Avoid openssl bug which prevent SSL connection to geocaching.com
Return missing import
Ignore parsing errors in cache details download

 * Prevent loss of data when error in parsing is encountered.
Refactor cache types; fixes

 * Move cache types to constants, add missing common cache types.
 * Refactor imports in several modules - use explicit agtl namespace to avoid conflicts.
 * Clean cache type parsing - reduce duplicity.
 * Fix download of overview over multiple pages.
Refactor the rest of imports.
Revert "N900 users can write Logs"

This reverts commit 4d624cc822e24a27c9aaf455ba6f91919f07d082.