Change Decl.Children implementation to be a map.
Change Decl.Children implementation to be a map.

Speeds up packages parsing. The 'test' now runs in 1 sec instead of 3.

mdempsky/gocode,syohex/gocode,suncycheng/gocode,kerr-huang/Gocode,TheBB/gocode,thousandhigh/gocode,fjl/gocode,mdempsky/gocode,thousandhigh/gocode,louiseGrandjonc/gocode,artnez/gocode,mem/gocode,TheBB/gocode,kerr-huang/Gocode,thousandhigh/gocode,beni55/gocode,kerr-huang/Gocode,artnez/gocode,MerlinDMC/gocode,mem/gocode,syohex/gocode,MerlinDMC/gocode,beni55/gocode,suncycheng/gocode,nsf/gocode,kerr-huang/Gocode,fjl/gocode,nsf/gocode,nsf/gocode,beni55/gocode,toqueteos/LightTable-Go,ghiden/gocode,lmh008/gocode,louiseGrandjonc/gocode,nsf/gocode,lmh008/gocode,beni55/gocode,ghiden/gocode,TheBB/gocode,louiseGrandjonc/gocode,mem/gocode,lmh008/gocode,artnez/gocode,syohex/gocode,suncycheng/gocode,syohex/gocode,mattn/gocode,MerlinDMC/gocode,thousandhigh/gocode,TheBB/gocode,fjl/gocode,toqueteos/LightTable-Go,louiseGrandjonc/gocode,artnez/gocode,mattn/gocode,ghiden/gocode,lmh008/gocode,suncycheng/gocode,mdempsky/gocode,mattn/gocode,ghiden/gocode,MerlinDMC/gocode,fjl/gocode,mem/gocode,mattn/gocode