Coding - Bump version to 8.0.0.dev (#394)

Coding - Bump version to 8.0.0.dev (#394)

New maintaining schema will be applied:
 maintenance stable release on top of minor (3 times per year).
   with binary compatible changes
   name - 7.9.1, 7.9.2, 7.9.3
 development fully-tested release based on master (every 5+- weeks)
    no binary compatible changes
    the latest features available the same as in master
    name - 8.0.0.rc1, 8.0.0.rc2, 8.0.0.rc3,...
the weekly branch IR still will be weekly and usually type of release will be "dev"
  of the next minor release. In current case "8.0.0".