removed reference to correlator.exe

- correlator.exe is no longer part of EUDAQ (?)
- this addresses issue eudaq/eudaq#16
added version preprocessor define determined through CMake from git information

- determines EUDAQ version from git or main CMake EUDAQ version
- adds "config.h" file with appropriate defines
- display version string in onlinemon and in eurun
- fixes issue eudaq/eudaq#24
replaced RootMonitor description and images with OnlineMon documentation

- RootMonitor is no longer part of EUDAQ
- addresses issue eudaq/eudaq#16
added information on TLU producer's requirements and on available optional parts
removed image missed in commit ddec3bc909d3ad434e51f89969d634cbaa46c723
replaced "tluonroot" documentation with the more modern approach of udev rules

- addresses eudaq/eudaq#16