consolidate the init steps for dapp

[sreuland]

there was some corner cases in dapp init, suggestion here to funnel everything through npm run reset, don't tell users to run any .sh scripts directly, leads to incomplete init states. always purge the target directory, as it was previously left dirty and contract bindings were pulling that older contract code.

[sreuland]

@chadoh, I tested the following back-back scenario between networks, to check reset behavior:

# test standalone
quickstart.sh standalone &
NETWORK=standalone npm run reset
npm run dev
# dapp worked, able to min/pledge
#
# test futurenet
npm run reset
npm run dev
# dapp worked, able to min/pledge

the only functional change here from your branch is that clean is removing the target directory, which was where I had encountered problems due to having run the dapp prior and target was dirtly with old stuff