- Rename members of WPScalingParam to conform to guidelines
- Avoid casts from const to non-const types
- Modify getWpScaling function to handle case where the reference
  index is negative (see #733)
- Add helper function isWeighted to determine whether weighting
  parameters are present for any colour component
- Fix some indentation issues

1. enabling the encoder-side RD check of ISP mode when ACT is disabled at CU level
2. ACT intra RD code clean-up

JVET-N0146/N0162/N0442/N0153/N0262/N0440/N0086: applicable condition of DMVR and BDOF (Variable names are changed in WeightedPrediction.cpp)