doc: Scrubbed ALL sensor library descriptions

In an effort to clean-up and standardize UPM library
documentation, this commit updates (and in most cases,
unifies) the CMake description string AND CXX header
@comname string.

Strings were taken from datasheets when possible, spelling
mistakes were addressed, copy/paste errors where fixed,
Title Case was used, etc.

    * Tested/updated/added @web tags
    * Added/updated invalid sensor images
    * Added/updated @man tags, added missing manufacturers

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

src/groveemg/CMakeLists.txt

@@ -1,5 +1,5 @@
 set (libname "groveemg")
-set (libdescription "Groveemg muscle signal reader sensor module")
+set (libdescription "Electromyography (EMG) Sensor")
 set (module_src ${libname}.cxx)
 set (module_hpp ${libname}.hpp)
 upm_module_init(mraa)

src/groveemg/groveemg.hpp

@@ -37,18 +37,18 @@ namespace upm {
   /**
    * @library groveemg
    * @sensor groveemg
-   * @comname Grove EMG Sensor
+   * @comname Electromyography (EMG) Sensor
    * @type electric
    * @man seeed
    * @con analog
    * @deprecated This class is being replaced by EMG
    *
    * @brief API for the Grove EMG Muscle Signal Reader
-   * 
+   *
    * Grove EMG muscle signal reader gathers small muscle signals,
    * then processes them, and returns the result
    *
-   * @image html groveemg.jpg 
+   * @image html emg.jpg
    * @snippet groveemg.cxx Interesting
    */
   class GroveEMG {