Coverity updates/fixes from Nelson

Coverity updates/fixes from Nelson

* merges:
  Avoid warnings
  Coverity: Forward NULL: CID 32
  Coverity: Forward NULL: CID 33
  Coverity: Forward NULL: CID 34
  Coverity: Forward NULL: CID 35
  Coverity: Forward NULL: CID 37
  Coverity: Forward NULL: CID 38
  Coverity: Forward NULL: CID 39
  Coverity: Forward NULL: CID 42, 41
  Coverity: Forward NULL: CID 44, 43, 36
  Coverity: Forward NULL: CID 48
  Coverity: Forward NULL: CID 49
  Coverity: Forward NULL: CID 50
  Coverity: Forward NULL: CID 51
  Coverity: Forward NULL: CID 54, 53, 52
  Fix additional transcoding assertions
  Coverity: Negative returns: CID 121
  Update link to newest compface in INSTALL
  Coverity: Missing return: CID 604