Add serialization2.h to CMakeLists.txt.
Add serialization_stream.h to CMakeLists.txt.
Add TODOs according to Jakob's review.
Remove can_read(n)/offset() usage from test.
Remove m_streamHeader member.
Remove serialization stream header `block size` entry.
Cleanup serialization_stream.

Get rid of m_nextBlock, m_nextIndex, update_vars, fetch_next_block.
Make offset private.
Simplify serialization_stream::can_read.
Switch serialization block type to tracking offset rather than block number.
Get rid of constants no longer in use.
Apply #pragma pack for portability.
Turn cleanClose header field into a char.
Move serialization_stream implementation into cpp file.
Add support for opening for read only or write only.
Add ut-serialization stream_ro_wo test.
Reorder serialization_stream declaration.
Document public methods of serialization_stream.
Add serialization helper methods.

stream.serialize(v) is simply tpie::serialize(stream, v).
stream.serialize(a, b) is simply tpie::serialize(stream, a, b).
stream.unserialize(v) is simply tpie::unserialize(stream, v).
stream.unserialize(a, b) is simply tpie::unserialize(stream, a, b).
Remove useless comment from ut-serialization stream test.