Add in ROMS WAD option ln_rwd+changes for implicit Bed Friction for ln_wd option
Note no ramp placed on ROMS bed friction yet
CS15mini case added as a Test CASE
at this revision AMM15 with Pure sigma coords barotorpic runs for 4 days without failure
in with ROMS option with 20cm min deoth and 50 vertical levels
Both run for CS15mini
In real domains nothing done on reference level yet so real domains
must have not negative depth points yet.
But a basic test has been done in WAD channel test cases (WAD7)

No changes in Main line source yet. See the MY_SRC sub dir of CS15 and TEST_CASES/WAD
for actual code changes.