Comment 9 for bug 1577219

These are the details of my changes:

screenlets
----------
- remove non-existent dependencies
- update old dependency versions
- check individual screenlet's required dependencies at startup, instead after load
- weather plugin's weather.com api url fix

indiv-screenlets
----------------
- change from python-gtkmozembed to python-webkit
- import required dependencies with try-catch, to be able to alert the user for missing dependencies
- some screenlets uses the weather api directly, not through the plugin, so I fixed the urls there also

The following screenlets are not working:
- EMHI
- evolutionContacts
- funnyordie
- LinuxEstoriaStat
- LinuxSerbiaStat
- mainmenu
- places(?)

I tested with ubuntu 16.04 only.

With xfce and mate, there is no particular problem.

With LXCE, the TuxScreenlet not working, without error.

With unity, the screenlets daemon app indicator is not visible.