remove interesting vars set from solver, add operators for solver operations
remove interesting vars set from solver, add operators for solver operations

Ignore-this: cff498daa4acc9a2be35d36e0d88c504

darcs-hash:764f6cdcd7074c8420e6fb9cbffccb890584cf32

dpwright/jhc,dpwright/jhc,dpwright/jhc,dpwright/jhc