fixed typo at comment
added "Protocol" to client protocol which is used for simple shellscript client
added groovyclient.sh which is still a limited client
fixed a diffrence between class name and file name
arranged build configuration and had tests for unsupported feature ignored
added unsupported message with -Ck/-Cr for groovyclient.sh
fixed to display additionally client's usage at the end of session when no option
tweaked usage of groovyclient.sh
renamed groovyserver -> groovyserver.sh

'groovyclient.sh' is newly added and it must have a 'sh' extension to be distinguished from a native client.
If a script had a 'sh' extension and another one didn't in same directory, it would be ugly.
That's the reason. Anyway it's a issue of source code management.
When executables/dist, it will be renamed again and removed the 'sh' extension.
made 'assemble' task dependsOn 'compileC'
added 'distPi' task which generates a platform independent binary archive