Integrate checkpointing

See merge request !199

This is a raw copy from `feature/composite-scheme`

Also plug to checkpointing and add related tests

Add TinyMatrix's double-dot product

See merge request !198

Also add a bunch of non discard qualifiers for TinyMatrix and TinyVector
and forbids Frobenius norm for non floating point TinyMatrix

Fix directory automatic creation if missing

See merge request !197

Fix parallel checker for SubItem{Value,Array}

See merge request !196

It always reported (incorrectly) synchronization defect when item
dimension is smaller than subitem's.

fix a bunch of non standard c++ thanks to clang++

See merge request !195