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/itg3200/CMakeLists.txt

@@ -1,5 +1,5 @@
 set (libname "itg3200")
-set (libdescription "Digital Gyro")
+set (libdescription "3-axis Digital Gyroscope")
 set (module_src ${libname}.cxx)
 set (module_hpp ${libname}.hpp)
 upm_module_init(mraa)

src/itg3200/itg3200.hpp

@@ -38,11 +38,12 @@ namespace upm {
 /**
  * @library itg3200
  * @sensor itg3200
- * @comname ITG-3200 3-Axis Digital Gyroscope
+ * @comname 3-axis Digital Gyroscope
  * @altname Grove 3-Axis Digital Gyroscope
  * @type compass
  * @man seeed
  * @con i2c
+ * @web http://wiki.seeed.cc/Grove-3-Axis_Digital_Gyro/
  *
  * @brief API for the ITG-3200 3-Axis Digital Gyroscope
  *