FastSerializer: Use fixed sized Sequence directly as cache

Well, at least the allocated space is fixed size.
When passing that to XOutputStream, change the size in a hacky way.

Change-Id: I24fa134286e3086beda25c9a6915549e7c69119a
FastSerializer: Avoid some cycles when dealing with doubles

Would be easier to use OStringBuffer, but we can't get its pData member.
Also its append(double) is suboptimal (or anything that uses
rtl_str_valueOfDouble) - should be doing something like this commit.

Change-Id: I8f3140081a574a84f0e60dc85cce1bd2de23cd34
FastSerializer: Simplify OUString write a bit more

Change-Id: Ifa0746d635ec43cdc37867cf94bcc128bb8e2aca
inline TokenMap::getUtf8TokenName

Change-Id: Icd9c6ebc9feb3e7aba28b01729b582a8f49c832a
FastSerializer: Also use cache for writing to ForMerge if we are inside mark()

To ensure the correct order of calling ForMerge methods,
call flush always before touching maMarkStack.

This was the missing piece in optimizing write() methods,
because of writeBytes() checking each time what to call.
E.g. for Calc documents we don't use maMarkStack at all.
So, just transfer the output to proper "ForMerge" when inside mark()
and allow optimizations.
This commit makes write() methods almost 1/3 as fast.

Change-Id: I96c13888206c81f87e29b998839f78ea9d5570af
package: Add ZipOutputEntry to isolate deflating of streams.

Preparation commit for deflating streams in parallel.
We still use the same single XOutputStream (ByteChucker :-) for
sequential writing but this can now be changed more easily.

Change-Id: Idf26cc2187461660e31ac2e12c4708e761596fb2
package: ZipPackageStream: prefix members

Change-Id: I02a1c3189c6b52f4f539b0eaa8878985cae8b321
package: Add pure virtual ZipPackageEntry::saveChild()

..and adapt what needs to be changed.
So that, we can kill at least some usages of horrible ContentInfo struct.

Change-Id: I32d41f3b8ce2dfb65f0d1df18a540a3f67dcab6d
Move ZipPackageStream::saveChild to proper source file

Change-Id: Icd108215874e830e5c9587f7dbb38a7f11ee27c8
Remove pointless functions now that saveChild() is ZipPackageStream's member

Change-Id: Id43ec2e7ddb1035d3306170523764bb9a74c03b8