#340 [doc] taurus.core.epics API docs not built in RTD

[Carlos Pascual]

This is empty:
http://www.taurus-scada.org/en/stable/devel/api/taurus/core/epics.html

Compare with:
http://www.taurus-scada.org/en/stable/devel/api/taurus/core/tango.html

The problem is probably related to a failure in RTD to import the taurus.core.epics module (since no mockup is provided for the epics)