[#24] Fixed sources in cmake

Signed-off-by: Tobias Frisch <tfrisch@uni-koblenz.de>

config/Sources.cmake

 
 # adding all source files and header files of the framework:
 set(vkcv_sources
-		${vkcv_source}/vkcv/Context.hpp
+		${vkcv_include}/vkcv/Context.hpp
 		${vkcv_source}/vkcv/Context.cpp
 
 		${vkcv_include}/vkcv/Core.hpp