vdiv: Added vdiv C source.

Multiple changes related to building the vdiv c source w/c example.

    * Renamed GroveVdiv to vdiv (all cases) throughout source, examples,
    directory names, and documentation.

    * Added C source.

    * Tested C sensor code on edison

    * Updated CMakeLists.txt for examples-c to build from
    <sensorname>-c.  This was a small change to get c examples to build
    for sensors in which the C++ does NOT wrap the C.

    * Added C example for vdiv.

Signed-off-by: Noel Eck <noel.eck@intel.com>

examples/c/CMakeLists.txt

@@ -38,7 +38,7 @@ macro(add_custom_example example_bin example_src example_module_list)
       if (${module} STREQUAL "lcd")
         set(module "i2clcd")
       endif()
-      target_link_libraries (${example_bin} ${module})
+      target_link_libraries (${example_bin} ${module}-c)
     endforeach()
   else()
    MESSAGE(INFO " Ignored ${example_bin}")
@@ -94,6 +94,7 @@ add_example (urm37)
 add_example (urm37-uart)
 add_example (hka5)
 add_example (dfrorp)
+add_example (vdiv)
 
 # Custom examples
 add_custom_example (nmea_gps_i2c-example-c nmea_gps_i2c.c nmea_gps)