refactored ProjectFile, Project and ProjectManager
ProjectFile now has encoding and extension properties
Project has a function to getProjectFiles(), addProjectFile - updated removeFile
ProjectManager openFiles now returns a Promise that resolves with the array of file input handle
Merge branch 'alpha' of github.com:thehogfather/pvsio-web into alpha

# By PaoloMasci
# Via PaoloMasci
* 'alpha' of github.com:thehogfather/pvsio-web:
  bugfix (mistyped directory for d3)
  implemented quit Emulink function (Emulink menu)
  bugfix: toolbar colors were not updated when creating/opening charts + missing warning when creating new charts leads to deleting the current chart
  bugfix for SVG translate/zoom events + handler for translate/zoom events moved from Emulink to EmuchartsEditor
  event handlers moved from emuchart to emulink + implemented toolbar functionality for deleting nodes and transitions
  implemented new/create emuchart + moved svg event handlers from EmuchartEditor to Emulink
  implemented zoom-in and zoom-out functionalities in emulink
  minor change (adjusted max zoom level)
  implemented functions and forms for entering new constants and state variables in Emulink
  removed obsolete files
  implemented functions and forms for deleting nodes and transitions in Emulink diagrams
  minor change (css style)
  implemented functions and forms needed for creating/renaming states and transition from the emulink menu
  revised emulink architecture: emucharts editor (complete) + emucharts manager (complete) + pvs writer (to be implemented)
refactored pvssocketserver removed unused code and ensured consistency in token properties that deal with files - all file tokens now use filePath not fileName
added tracer to pvsprocess
fileHandler now resolves with filePath and fileContent
refactored ProjectManager to separate form interaction from data manipulation
added helper functions in ProjectFile for distinguishing image and pvs files
Refactored Project to remove pvsFiles, widgetDefintions, scripts and image properties all files now reside together in _projectFiles. Separate functions filter this list to expose the appropriate selection
Also removed path property since it is the same as name, removed unused code and unified file saving logic
Merge branch 'alpha' of github.com:thehogfather/pvsio-web into alpha

# By PaoloMasci
# Via PaoloMasci
* 'alpha' of github.com:thehogfather/pvsio-web:
  minor changes (added utility functions needed for saving emulink files)