make the execute command blocking until operation is finished

[marook]

When calling the execute_command the client should wait until the command has been fully executed within eclipse.

[marook]

Some hints about fixing this issue can be found here: https://github.com/marook/eclipse-remote-control/commit/ab67977f8d3d2d6bc0e977309bd4515748576a6f

[biou]

Indeed this could be interesting to integrate the execute_command calls in a batch or shell script. Also if we could have the output of the eclipse console redirected to stdout, this could be helpful!