Changes in diff_context.C for -Wshadow.
Changes in diff_context.C for -Wshadow.

Issue #24.

dmcdougall/libmesh,vikramvgarg/libmesh,libMesh/libmesh,jwpeterson/libmesh,BalticPinguin/libmesh,vikramvgarg/libmesh,Mbewu/libmesh,dknez/libmesh,dmcdougall/libmesh,coreymbryant/libmesh,hrittich/libmesh,permcody/libmesh,aeslaughter/libmesh,cahaynes/libmesh,pbauman/libmesh,karpeev/libmesh,balborian/libmesh,karpeev/libmesh,dschwen/libmesh,roystgnr/libmesh,hrittich/libmesh,coreymbryant/libmesh,dmcdougall/libmesh,giorgiobornia/libmesh,aeslaughter/libmesh,svallaghe/libmesh,dschwen/libmesh,libMesh/libmesh,coreymbryant/libmesh,90jrong/libmesh,benkirk/libmesh,dschwen/libmesh,giorgiobornia/libmesh,aeslaughter/libmesh,hrittich/libmesh,balborian/libmesh,permcody/libmesh,capitalaslash/libmesh,benkirk/libmesh,giorgiobornia/libmesh,jiangwen84/libmesh,karpeev/libmesh,svallaghe/libmesh,salazardetroya/libmesh,balborian/libmesh,karpeev/libmesh,friedmud/libmesh,balborian/libmesh,aeslaughter/libmesh,hrittich/libmesh,jwpeterson/libmesh,karpeev/libmesh,capitalaslash/libmesh,jiangwen84/libmesh,capitalaslash/libmesh,vikramvgarg/libmesh,90jrong/libmesh,balborian/libmesh,benkirk/libmesh,friedmud/libmesh,Mbewu/libmesh,libMesh/libmesh,pbauman/libmesh,aeslaughter/libmesh,pbauman/libmesh,jwpeterson/libmesh,markcmiller86/libmesh_silo,capitalaslash/libmesh,benkirk/libmesh,vikramvgarg/libmesh,svallaghe/libmesh,benkirk/libmesh,BalticPinguin/libmesh,permcody/libmesh,dknez/libmesh,BalticPinguin/libmesh,permcody/libmesh,vikramvgarg/libmesh,friedmud/libmesh,90jrong/libmesh,jiangwen84/libmesh,jiangwen84/libmesh,friedmud/libmesh,giorgiobornia/libmesh,capitalaslash/libmesh,aeslaughter/libmesh,Mbewu/libmesh,friedmud/libmesh,dmcdougall/libmesh,svallaghe/libmesh,benkirk/libmesh,libMesh/libmesh,hrittich/libmesh,svallaghe/libmesh,BalticPinguin/libmesh,coreymbryant/libmesh,karpeev/libmesh,cahaynes/libmesh,roystgnr/libmesh,svallaghe/libmesh,Mbewu/libmesh,giorgiobornia/libmesh,salazardetroya/libmesh,libMesh/libmesh,dschwen/libmesh,jwpeterson/libmesh,giorgiobornia/libmesh,Mbewu/libmesh,jwpeterson/libmesh,salazardetroya/libmesh,roystgnr/libmesh,karpeev/libmesh,pbauman/libmesh,BalticPinguin/libmesh,libMesh/libmesh,capitalaslash/libmesh,svallaghe/libmesh,dmcdougall/libmesh,90jrong/libmesh,giorgiobornia/libmesh,capitalaslash/libmesh,dmcdougall/libmesh,90jrong/libmesh,roystgnr/libmesh,friedmud/libmesh,balborian/libmesh,jwpeterson/libmesh,Mbewu/libmesh,Mbewu/libmesh,salazardetroya/libmesh,friedmud/libmesh,balborian/libmesh,pbauman/libmesh,friedmud/libmesh,coreymbryant/libmesh,dknez/libmesh,dknez/libmesh,vikramvgarg/libmesh,90jrong/libmesh,balborian/libmesh,salazardetroya/libmesh,hrittich/libmesh,aeslaughter/libmesh,roystgnr/libmesh,hrittich/libmesh,giorgiobornia/libmesh,dknez/libmesh,aeslaughter/libmesh,benkirk/libmesh,libMesh/libmesh,vikramvgarg/libmesh,markcmiller86/libmesh_silo,benkirk/libmesh,balborian/libmesh,markcmiller86/libmesh_silo,benkirk/libmesh,dknez/libmesh,giorgiobornia/libmesh,90jrong/libmesh,90jrong/libmesh,dschwen/libmesh,permcody/libmesh,salazardetroya/libmesh,dschwen/libmesh,coreymbryant/libmesh,coreymbryant/libmesh,coreymbryant/libmesh,jiangwen84/libmesh,balborian/libmesh,permcody/libmesh,BalticPinguin/libmesh,salazardetroya/libmesh,dmcdougall/libmesh,cahaynes/libmesh,jiangwen84/libmesh,BalticPinguin/libmesh,cahaynes/libmesh,dknez/libmesh,markcmiller86/libmesh_silo,cahaynes/libmesh,roystgnr/libmesh,cahaynes/libmesh,Mbewu/libmesh,permcody/libmesh,markcmiller86/libmesh_silo,friedmud/libmesh,hrittich/libmesh,cahaynes/libmesh,capitalaslash/libmesh,dschwen/libmesh,roystgnr/libmesh,dschwen/libmesh,hrittich/libmesh,salazardetroya/libmesh,karpeev/libmesh,svallaghe/libmesh,jiangwen84/libmesh,dmcdougall/libmesh,permcody/libmesh,markcmiller86/libmesh_silo,vikramvgarg/libmesh,pbauman/libmesh,cahaynes/libmesh,roystgnr/libmesh,markcmiller86/libmesh_silo,Mbewu/libmesh,pbauman/libmesh,dknez/libmesh,pbauman/libmesh,jwpeterson/libmesh,BalticPinguin/libmesh,libMesh/libmesh,pbauman/libmesh,90jrong/libmesh,jwpeterson/libmesh,svallaghe/libmesh,vikramvgarg/libmesh,jiangwen84/libmesh,markcmiller86/libmesh_silo,aeslaughter/libmesh