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/grovegsr/CMakeLists.txt

@@ -1,5 +1,5 @@
 set (libname "grovegsr")
-set (libdescription "Grovegsr galvanic skin response sensor module")
+set (libdescription "Galvanic Skin Response (GSR) Sensor")
 set (module_src ${libname}.cxx)
 set (module_hpp ${libname}.hpp)
 upm_module_init(mraa)

src/grovegsr/grovegsr.hpp

@@ -37,7 +37,7 @@ namespace upm {
   /**
    * @library grovegsr
    * @sensor grovegsr
-   * @comname Grove GSR Sensor
+   * @comname Galvanic Skin Response (GSR) Sensor
    * @type electric
    * @man seeed
    * @con analog
@@ -50,7 +50,7 @@ namespace upm {
    * In other words, it measures sweat on your fingers
    * as an indicator of strong emotional reactions.
    *
-   * @image html grovegsr.jpg
+   * @image html gsr.jpg
    * @snippet grovegsr.cxx Interesting
    */
   class GroveGSR {