Further console improvements

- adjusted documentation of set and call for the help command
- fixed typo in paramater "ObjectAndVarialble" of set()
- added watch and unwatch commands
- added optional parameter to watch which adds the field changed to the
watch window afterwards
- abstracted the parsing of ObjectAndVariable into a function called
resolveObjectAndVariable() which is also needed for watch and unwatch
- added security check to resolveObjectAndVariable() code to prevent
crash when passing an ObjectAndVariable string without the "." delimiter
Merge pull request #358 from Gama11/dev_console

Further console improvements