Add key mappings for Kana, Eisu_toggle and Muhenkan

[tom-tan]

This request is a continuation of #818 to share Japanese keyboards with Windows and mac computers while keeping Japanese input functionalities.

Windows and mac provide similar but different keys to enable and disable Japanese input methods:

• Disable Japanese input method: Muhenkan (Windows) <-> Eisu_toggle (mac)
• Enable Japanese input method: Henkan (Windows) <-> Kana (mac)

Making a mapping of these keys is important to share the Japanese keyboards but unfortunately some of these keys are not recognized by barrier.

The request #818 added key entries for Eisu_toggle and Muhenkan to the barrier internal key representation.
This request adds a mapping between the internal representation with OS-specific key representation.

I confirmed that this request makes barrier aware of Kana, Eisu_toggle, Henkan and Muhenkan keys in the section: options section in the setting file.

After merging this request, we can smoothly share Japanese keyboards between Windows and mac computers by adding the following settings (in the case of Windows server):

section: options
        ...
	keystroke(Henkan) = ;keystroke(Kana,client)
	keystroke(Muhenkan) = ;keystroke(EisuToggle,client)
end

Note that GUI hotkey editor does not recognize these Japanese IME keys and therefore we have to edit the configuration file directly. Fixing it is out of scope of this request.

[tom-tan]

I found that in the case of Windows server and mac client with the above example configuration, it works in mac client but I cannot enable and disable Japanese input method using Henkan and Muhenkan in Windows server.

However, I reproduce the same problem with keystroke(Control+a) = ;keystroke(Control+a,client).
Therefore it is not due to this request and it should be filed in another issue.

[tom-tan]

I filed another blocker to share Japanese keyboards with Windows and mac computer while enabling/disabling Japanese input method using the same keys in #840.

[tom-tan]

ping!

[p12tic]

Looks good, thanks for working on this.

[tom-tan]

Thanks!