Remove some stuff that is throwing errors in gcc-7

Remove some stuff that is throwing errors in gcc-7

New gcc warns (and errors with -Werror) if there are unused functions or
variables.

- Remove two leftover functions from ae34634113b2
- Remove definition made to much in 035c3253ded5
- Remove two variable definitions made in b0b11291d2c9
- Remove not really used function in 15917d4063ce
- Remove two variable definitions made in 5ed2574fb8cc
- Remove variable definition made in efe0e6a38273
- Remove variable definition made in c95bd6996583 and since then removed
  usage
- Remove unused variable definition made in bc02fd0eb0d9
- Remove unused variable definition made in 324129463b17
- Remove two variables left over from fe69cac65ad4 (Pretty old code from
  John Ellis)
- Remove some functions not used anymore with one obsolete variable
- Remove Variables introduced in 8746b22d3ed1 and 51a9455bd33f
- Fix missed change in definition in 6e3b2edff8cf
- Remove unused function from 63a96f8504a2
- Remove unused function from c6bdbaa559c7 (Pretty old code)