This is a combination of 2 commits.

aio: mraa_aio_read (v1.0.0) can now return -1, treat that in sensors using it

Adds alot of exceptions if the aio read goes wrong

Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
Signed-off-by: Noel Eck <noel.eck@intel.com>

src/grovevdiv/grovevdiv.cxx

@@ -53,6 +53,7 @@ unsigned int GroveVDiv::value(unsigned int samples)
   for (int i=0; i<samples; i++)
     {
       sum += mraa_aio_read(m_aio);
+      if (sum == -1) return 0;
       usleep(2000);
     }