Ability to pass false booleans via the cli

[theethernaut]

Atm, calling something like

zos create MyContract --init --args false

cli/src/utils/input.ts will parse false as the string "false", and when this value is passed to lib/helpers/encodeCall.ts, the encoding will interpret "false" as the boolean true.

input.ts should account for such booleans (as opposed to encodeCall.ts doing it in order to maintain compatibility with Web3).