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/ads1x15/CMakeLists.txt

@@ -1,5 +1,5 @@
 set (libname "ads1x15")
-set (libdescription "Analog to digital converter")
+set (libdescription "Texas Instruments I2C ADC Library")
 set (module_src ${libname}.cxx ads1115.cxx ads1015.cxx)
 set (module_hpp ${libname}.hpp ads1115.hpp ads1015.hpp)
 upm_module_init(interfaces mraa)

src/ads1x15/ads1015.hpp

@@ -57,11 +57,11 @@ namespace upm {
   /**
    * @library ads1x15
    * @sensor ADS1015
-   * @comname ADS1015 ADC
+   * @comname 12-bit ADC with Integrated MUX, PGA, Comparator, Oscillator, and Reference
    * @type electric
    * @man ti adafruit
    * @con i2c
-   * @web web http://www.ti.com/lit/ds/symlink/ads1015.pdf
+   * @web http://www.ti.com/lit/ds/symlink/ads1015.pdf
    *
    * @brief API for ADS1015
    *

src/ads1x15/ads1115.hpp

@@ -57,7 +57,7 @@ namespace upm {
   /**
    * @library ads1x15
    * @sensor ADS1115
-   * @comname ADS1115 ADC
+   * @comname 16-bit ADC with Integrated MUX, PGA, Comparator, Oscillator, and Reference
    * @type electric
    * @man ti adafruit
    * @con i2c