The lookup of getNumberFormatKeyByIndex() is sped up by storing the
addresses into the cached data array m_aDataArray.

The existing cache invalidating strategy should hold since the
cache was already storing information about hidden fields and
ranges, which is the information which affects the addresses.

Also: Change data type of m_aDataArray from std::list to std::vector to
allow index-based access.

Also: Change for-loops over m_aDataArray to range-based loops with auto
variables to make them more readable

Change-Id: I9a5038892a384e7d5e72556a52faaf98b475a839
Reviewed-on: https://gerrit.libreoffice.org/16485Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Eike Rathke <erack@redhat.com>
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>