s/IsAction/IsValidAction/
s/IsEnvironment/IsValidEnvironment/
s/IsMachine/IsValidMachine/
unexport IsValidEnvironment
s/IsNetwork/IsValidNetwork/
unexport isRelation and rename.
s/IsService/IsValidService/
s/IsUnit/IsValidUnit/
s/IsUser/IsValidUser/
Merge pull request #16 from howbazaar/valid-names

Rename Is<thing> functions to IsValid<thing>