Merge branch 'jinyuntang/lnd/betr_v2int' into next (PR #1618)

This replaces betr-v1 with the more modularized betr-v2. The code run
successfully with gnu compiler on edison, however, it requires intel
'compiler 16.x to run and 15.x can only run in the debug model.
This replacement does not affect other parts of ALM other than betr.

[BFB]