Fix capital letters in cmake find module package name

[VictorLamoine]

This is a follow up to #45

The standard _INCLUDE_DIRS and _BINARY_DIR etc.. should respect package name capitalization; https://gitlab.kitware.com/cmake/community/wikis/doc/tutorials/How-To-Find-Libraries

This is not a functional change, this help removes warning when catkin (from Robot Operating System) expects the right capitalization:

CMake Warning at /opt/ros/kinetic/share/catkin/cmake/catkin_package.cmake:166 (message):
  catkin_package() DEPENDS on 'libsocket' but neither
  'libsocket_INCLUDE_DIRS' nor 'libsocket_LIBRARIES' is defined.
Call Stack (most recent call first):
  /opt/ros/kinetic/share/catkin/cmake/catkin_package.cmake:102 (_catkin_package)
  keyence_experimental/CMakeLists.txt:22 (catkin_package)

@AustinDeric , @Jmeyer1292 this is useful for my rework of the Keyence experimental package (I have not yet made a pull request)