Resolve "E-logbook API change"

Closes #2 (closed)

Sessions implementation.

Elogbook: Some cosmetic work to make the html output in the browser look better, i.e. multi-line logs are now spaced by single line, compared to double lines before. Implementation of the BEAMLINE logbook. Using the command elogon beamline to activate this mode. elogon proposal will revert that mode. elogoff will switch both modes off.