BOY: add ConsoleUtil.writeString(string, r,g,b) to allow writing
colorful text in console.
BOY: Fix a bug that error information from executed command may be
ignored: https://github.com/ControlSystemStudio/cs-studio/issues/215
Merge pull request #217 from ControlSystemStudio/hotfixes

BOY bug in error information from exec command: resolves #215