Activesync fixes

[amulet1]

Remove range usage and harden SEARCH_AND in _doQuery()

• Remove erroneous $range parameter from recursive SEARCH_AND call and
  eliminate (a non-working) per-mailbox range slicing, as range handling
  belongs (and is already done) at the caller level. Add explicit validation
  to SEARCH_AND unwrapping.

Remove reference return from __get() magic method in Horde_ActiveSync_Message_Base

Harden WBXML decoder against false/empty element checks (to be continued)

• Replace empty()/loose-equality checks with strict !== false comparisons
• Fix getElement() logic: return element directly for start/end tags,
  only loop for content concatenation; eliminates spurious return false
• Add missing return false at end of _getToken() (potential null return bug)
• Fix typo: "memeory" -> "memory" in comment
• Update @return docblocks to reflect array|boolean return types

Overhaul Search request handling with proper range validation and status codes

• Add STORE_STATUS_RANGEERR (12) constant per MS-ASCMD spec
• Add default case to search name switch; return STORE_STATUS_PROTERR for
  unknown store types
• Add per-type max results limits (mailbox/GAL: 100, documentlibrary: 1000)
• Move range parsing out of query map into dedicated $range variable;
  validate format and enforce max results ceiling, returning RANGEERR (12) if exceeded
  [this also fixes issue with caching done by getSearchResults()];
• Fix mailbox/documentlibrary error status: PROTERR instead of FOLDERSYNC
• Move pagination (array_slice) from driver into request handler; driver
  now returns full result set, caller owns slicing
• Replace search_result['rows']/['total'] envelope with flat $rows/$total
• Simplify output loop: drop manual $count, derive search_range from
  $start + count($rows)
• Gate backend call behind $store_status === SUCCESS check

IMPORTANT: This is required by and relies on changes in horde/Core#57.