Cleanup: Combined File, Path and Directory into FS

- The three objects are related and always travel together, so they are now
  combined.

test/CMakeLists.txt

@@ -4,7 +4,7 @@ include_directories (${CMAKE_SOURCE_DIR}
                      ${CMAKE_SOURCE_DIR}/test
                      ${TASKSH_INCLUDE_DIRS})
 
-set (test_SRCS color.t path.t file.t directory.t)
+set (test_SRCS color.t fs.t)
 
 message ("-- Configuring run_all")
 if (${CMAKE_SOURCE_DIR} STREQUAL ${CMAKE_BINARY_DIR})
@@ -35,9 +35,7 @@ add_custom_target (build_tests DEPENDS ${test_SRCS}
 foreach (src_FILE ${test_SRCS})
   add_executable (${src_FILE} "${src_FILE}.cpp"
                               ../src/Color.cpp
-                              ../src/Path.cpp
-                              ../src/File.cpp
-                              ../src/Directory.cpp
+                              ../src/FS.cpp
                               ../src/text.cpp
                               test.cpp)
   target_link_libraries (${src_FILE} ${TASKSH_LIBRARIES})