remove . at the end also, result of 0's being removed
more details when JSON fails to parse
create _apiget for a common 'GET' function, use it from _apiprice
create _apifee to get fee info, use _apiget
add BtceFee('btc_usd') function, use _apifee
set 'pair' only if $exchange is defined for cleanliness (not strictly required)
clean all numbers in a foreach loop instead of duplicating all bits per var
do retries on mech bits also, for now duplicated