I have this same issue.
Even running the default demo sketches have the declaring issue.
I encountered the same problem.Removing the files - libraries\RobotIRremote\IRremoteTools.cpp and libraries\RobotIRremote\IRremoteTools.h solved the problem. They are example files which somehow are getting included. You can move those two files to some other location as backup.
surprisingly when tried to upload the LIFA base with old arduino IDE which is version 1.0.1 it gets successful
what can i do to solve it?