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/flex/CMakeLists.txt

@@ -1,5 +1,5 @@
 upm_mixed_module_init (NAME flex
-    DESCRIPTION "Resistive flex sensor"
+    DESCRIPTION "Resistive Flex Sensor"
     C_HDR flex.h
     C_SRC flex.c
     CPP_HDR flex.hpp

src/flex/flex.hpp

@@ -37,7 +37,7 @@ namespace upm {
   /**
    * @library flex
    * @sensor flex
-   * @comname Flex Sensor
+   * @comname Resistive Flex Sensor
    * @type flexfor
    * @man sparkfun
    * @web https://www.sparkfun.com/products/8606