Simplify InfHex18::key(side).
Simplify InfHex18::key(side).

Implement in terms of InfHex::key(side) as much as possible.

BalticPinguin/libmesh,benkirk/libmesh,svallaghe/libmesh,dschwen/libmesh,BalticPinguin/libmesh,capitalaslash/libmesh,capitalaslash/libmesh,BalticPinguin/libmesh,roystgnr/libmesh,benkirk/libmesh,giorgiobornia/libmesh,balborian/libmesh,aeslaughter/libmesh,pbauman/libmesh,svallaghe/libmesh,capitalaslash/libmesh,BalticPinguin/libmesh,hrittich/libmesh,dschwen/libmesh,vikramvgarg/libmesh,BalticPinguin/libmesh,balborian/libmesh,giorgiobornia/libmesh,hrittich/libmesh,hrittich/libmesh,friedmud/libmesh,giorgiobornia/libmesh,90jrong/libmesh,friedmud/libmesh,pbauman/libmesh,friedmud/libmesh,90jrong/libmesh,dschwen/libmesh,pbauman/libmesh,balborian/libmesh,hrittich/libmesh,dknez/libmesh,benkirk/libmesh,roystgnr/libmesh,hrittich/libmesh,dknez/libmesh,coreymbryant/libmesh,capitalaslash/libmesh,libMesh/libmesh,90jrong/libmesh,friedmud/libmesh,BalticPinguin/libmesh,aeslaughter/libmesh,jwpeterson/libmesh,jwpeterson/libmesh,benkirk/libmesh,pbauman/libmesh,friedmud/libmesh,capitalaslash/libmesh,dknez/libmesh,coreymbryant/libmesh,dknez/libmesh,svallaghe/libmesh,aeslaughter/libmesh,BalticPinguin/libmesh,roystgnr/libmesh,90jrong/libmesh,giorgiobornia/libmesh,benkirk/libmesh,coreymbryant/libmesh,balborian/libmesh,dknez/libmesh,aeslaughter/libmesh,friedmud/libmesh,pbauman/libmesh,hrittich/libmesh,jwpeterson/libmesh,dschwen/libmesh,jwpeterson/libmesh,giorgiobornia/libmesh,vikramvgarg/libmesh,giorgiobornia/libmesh,hrittich/libmesh,90jrong/libmesh,dschwen/libmesh,benkirk/libmesh,roystgnr/libmesh,balborian/libmesh,benkirk/libmesh,vikramvgarg/libmesh,balborian/libmesh,libMesh/libmesh,jwpeterson/libmesh,90jrong/libmesh,friedmud/libmesh,libMesh/libmesh,coreymbryant/libmesh,vikramvgarg/libmesh,dschwen/libmesh,vikramvgarg/libmesh,pbauman/libmesh,hrittich/libmesh,libMesh/libmesh,aeslaughter/libmesh,roystgnr/libmesh,balborian/libmesh,roystgnr/libmesh,libMesh/libmesh,capitalaslash/libmesh,giorgiobornia/libmesh,svallaghe/libmesh,BalticPinguin/libmesh,jwpeterson/libmesh,vikramvgarg/libmesh,90jrong/libmesh,90jrong/libmesh,dschwen/libmesh,balborian/libmesh,coreymbryant/libmesh,libMesh/libmesh,svallaghe/libmesh,jwpeterson/libmesh,aeslaughter/libmesh,svallaghe/libmesh,dknez/libmesh,coreymbryant/libmesh,hrittich/libmesh,jwpeterson/libmesh,friedmud/libmesh,libMesh/libmesh,svallaghe/libmesh,aeslaughter/libmesh,dschwen/libmesh,libMesh/libmesh,balborian/libmesh,roystgnr/libmesh,giorgiobornia/libmesh,dknez/libmesh,roystgnr/libmesh,aeslaughter/libmesh,vikramvgarg/libmesh,coreymbryant/libmesh,pbauman/libmesh,vikramvgarg/libmesh,benkirk/libmesh,pbauman/libmesh,benkirk/libmesh,aeslaughter/libmesh,giorgiobornia/libmesh,svallaghe/libmesh,svallaghe/libmesh,coreymbryant/libmesh,vikramvgarg/libmesh,90jrong/libmesh,pbauman/libmesh,friedmud/libmesh,capitalaslash/libmesh,capitalaslash/libmesh,balborian/libmesh,dknez/libmesh