hledger-vty-0.15: dependencies

Dependencies for hledger-vty-0.15

hledger-vty	base (>=3 && <5) cmdargs (>=0.8 && <0.9) hledger (==0.15) hledger-lib (==0.15) HUnit safe (>=0.2) time vty (>=4.6.0.1 && <4.8)