cleanup cmake project to move build instructions to toplevel

protocol/CMakeLists.txt

@@ -0,0 +1,13 @@
+cmake_minimum_required(VERSION 3.0.0)
+
+project(slider-protocol C)
+
+add_library(slider-protocol INTERFACE)
+
+# add_sources(slider-protocol
+# PUBLIC
+#     communication.h
+#     interface.h
+# )
+
+target_include_directories(slider-protocol INTERFACE ${CMAKE_CURRENT_SOURCE_DIR})