Add of an empty Monitoring tab

* Added a responsive Monitoring section in the project explorer
* Removed no more used Results and Output sections in the project explorer

(references #78)
Add of observers paths in Preferences

(references #78)
Add of a front controler for MonitoringDescriptor

* Created BuilderMonitoring class and test cases
* Monitoring module and related classes now use BuilderMonitoring instead of MonitoringDescriptor
* Added observers extra paths from preferences at Builder start
* Added check of observers availability at Project build

(references #78)
First rough version of monitoring tab

(references #78)
Fix of observers default path in Preferences dialog box

(references #78)
Add of "Add Observers" dialog box

(references #78)
Add of "Edit observer parameters" dialog box

* Made Builder aware if smth changed in Monitoring
* Added function to clear all parameters of a descriptor

(references #78)
Improve of Monitoring tab design

(references #78)
Improve of "Add observer" dialog box design

(references #78)
Improve of "Edit observer parameters" dialog box design

(references #78)
Make Builder reacts to changes of observers paths

* Made Builder reacts to changes of observers paths in Preferences dialog box
* Refactored Monitoring checking
* Added check of monitoring before close of Preferences dialog box, user can now cancel close of this box if he doesn't approve proposed changes
* Changed Preferences dialog box call, now may take EngineProject as parameter, allowing this box to make checks by itself

(references #78)
Improve of Monitoring list and parameters design

(closes #78)