Provide BaseTool2 class for tool-info modules
Provide BaseTool2 class for tool-info modules

For now is is just copied from BaseTool but will be changed to a new API.
The only change is a reordering of the methods in the source.

This is the start of the necessary steps for #256.

ultimate-pa/benchexec,sosy-lab/benchexec,ultimate-pa/benchexec,ultimate-pa/benchexec,sosy-lab/benchexec,ultimate-pa/benchexec,sosy-lab/benchexec,dbeyer/benchexec,dbeyer/benchexec,sosy-lab/benchexec,dbeyer/benchexec,sosy-lab/benchexec,ultimate-pa/benchexec,dbeyer/benchexec,sosy-lab/benchexec,ultimate-pa/benchexec