Remove a C-lang client
Remove a ruby client
Remove a bash client
Remove bash and DOS server commands and a ServerCLI which is used by them
Tweak build.gradle
Upgrade JNA to 4.1.0
Upgrade Groovy to 2.3.3
Use Makefile to compile Go sources from build.gradle
Revert "Use Makefile to compile Go sources from build.gradle"

This reverts commit edd32e5bced6351d5075a603bd8191ab88e1e816.

Because you could not build at a environment where there is no 'make' command, like Windows.
Add Makefile to build manually commands written by golang
Tweak go sources about a version
Change a package "org.jggug.kobo.groovyserv" to "groovyx.groovyserv"