there might be other variants out there in practice, but this
works for default encrypted xls of excel 2013

(cherry picked from commit 1473ce03)

contains...

be more c++y

Change-Id: I673b00e111a734bc626ba3d3f6ecf9692f1ce7db
(cherry picked from commit fcf7f503)

hash len is 20 for xls cryptoapi configuration

Change-Id: I6e06b8578959b8147043179db57e875b1d98d57d
(cherry picked from commit 49188435)

clarify hash lengths a bit more

Change-Id: I66cea4b9efb82d29e6c052ac11a6f2eaca823ce0
(cherry picked from commit 8db1b13e)

hash len isn't going to change depending on who implements it

Change-Id: Iee585cba4acad74c11d083085153e2af96c8894f
(cherry picked from commit fcc846e8)

move some useful header information to mscodec for reuse

Change-Id: Ic7adf3ed3c8279cc93a06975d6fb337210d1af87
(cherry picked from commit fc514cbf)

rework things in light of now available documentation

Change-Id: If5f75e27191017a8c6a3929e2a70d21840f157c6
(cherry picked from commit 3fabbd0a)

split MSCodec_Std97 into a baseclass MSCodec97

(cherry picked from commit 06916c83)

Change-Id: Ia3c41a048169c78684800def94e53fc9f3201e30

Change-Id: I91c0e1d1d95fbd1c68966650e7ac7d23276bcbe3
Reviewed-on: https://gerrit.libreoffice.org/30128Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Stahl <mstahl@redhat.com>