Adding support for RVV10+SCAN functional (and any metaGGA+VDW in general)
Support for RVV10+SCAN as reported in PHYSICAL REVIEW X 6, 041005 (2016), which requires using a different value of the parameter "b" in RVV10. CHanges in the code:
- Modules/xc_rVV10.f90 : rvv10 takes an optional parameter to specify the value of b
- PW/src/v_of_rho.f90 : v_xc_meta calls nlc to apply non-local XC
- Modules/funct.f90 : new shortname rvv10-scan defined and nlc modified to call rvv10 with b=15.7 when imeta=5 is detected
Note that you still (as of june 2018) need to compile QE with pre-release version of libxc in order to have the SCAN functional.