Implement help command for dicttoolkit.

native/dicttoolkit/src/command_executors/diff_executor.cpp

native/dicttoolkit/src/command_executors/diff_executor.h

native/dicttoolkit/src/command_executors/header_executor.cpp

native/dicttoolkit/src/command_executors/header_executor.h

native/dicttoolkit/src/command_executors/help_executor.cpp

native/dicttoolkit/src/command_executors/help_executor.h

native/dicttoolkit/src/command_executors/info_executor.cpp

native/dicttoolkit/src/command_executors/info_executor.h

...e/dicttoolkit/src/command_executors/makedict_executor.cpp

native/dicttoolkit/src/command_executors/makedict_executor.h