Add safe_bool<T> class recommended by @roystgnr.
Add safe_bool<T> class recommended by @roystgnr.

This class can be used to make C++98 operator bool () implementations
act more like "explicit" conversion operators even though that is not
allowed in C++98.

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