Fix README.
Fix README.

Fixes #7.

jaynus/entityx,arvidsson/entityx,alecthomas/entityx,asmodehn/entityx,drewet/entityx,alecthomas/entityx,arvidsson/entityx,drewet/entityx,jarrettchisholm/entityx,jaynus/entityx,asmodehn/entityx,Bablawn3d5/entityx,Bablawn3d5/entityx,arvidsson/entityx,jaynus/entityx,alecthomas/entityx,asmodehn/entityx,jarrettchisholm/entityx,Bablawn3d5/entityx,jarrettchisholm/entityx,drewet/entityx,asmodehn/entityx