Saving PartActivated event

Whenever you change tabs (=part), it's saved to log with a "@".
Related to issue karlitrotski/CodingSpectator/#10.
Pair programming with @JurajKubelka
PartListener uses IPartListener2.

It changes interface in order to obtain more events which inform us about parts (=tabs) usage.
Related to issue karlitrotski/CodingSpectator/#10
Pair programming with @JurajKubelka
New PartOperation class

We have changed PartActivatedOperation to more general class in order to avoid too many classes related to Part events.
Related to issue karlitrotski/CodingSpectator/#10
Pair programming with @JurajKubelka
Saving parts' events

Has been added OPENED, HIDDEN, VISIBLE as parts' events.
Related to issue karlitrotski/CodingSpectator/#10.
Pair programming with @JurajKubelka
Merge branch 'cinai-issue10'