Resolve #460: Add wallet_scan_progress entry in wallet_get_info output
Resolve #460: Add wallet_scan_progress entry in wallet_get_info output

The wallet now reports its progress as a float in [0,1] any time it
rescans the blockchain. This float is published via the wallet_get_info
output. In the case of some error during rescanning, the value will be
set to -1.

jakeporter/Bitshares,dacsunlimited/dac_play,jakeporter/Bitshares,drltc/keyid,dacsunlimited/dac_play,bitsuperlab/cpp-play,bitshares/bitshares-0.x,bitshares/bitshares,frrp/bitshares,jakeporter/Bitshares,jakeporter/Bitshares,FollowMyVote/bitshares,bitsuperlab/cpp-play,bitshares/bitshares-0.x,dacsunlimited/dac_play,bitsuperlab/cpp-play,camponez/bitshares,bitshares/bitshares,drltc/keyid,Ziftr/bitshares,bitshares/bitshares,denkhaus/bitsharesx,frrp/bitshares,denkhaus/bitsharesx,RemitaBit/Remitabit,bitshares/devshares,bitshares/devshares,camponez/bitshares,denkhaus/bitsharesx,drltc/keyid,dacsunlimited/dac_play,bitshares/devshares,RemitaBit/Remitabit,RemitaBit/Remitabit,bitshares/bitshares-0.x,bitsuperlab/cpp-play,FollowMyVote/bitshares,FollowMyVote/bitshares,bitshares/bitshares-0.x,bitshares/devshares,FollowMyVote/bitshares,drltc/keyid,bitsuperlab/cpp-play,bitshares/bitshares,jakeporter/Bitshares,bitshares/bitshares,bitsuperlab/cpp-play,FollowMyVote/bitshares,frrp/bitshares,bitshares/bitshares-0.x,Ziftr/bitshares,frrp/bitshares,frrp/bitshares,frrp/bitshares,bitshares/devshares,camponez/bitshares,bitshares/bitshares,RemitaBit/Remitabit,FollowMyVote/bitshares,camponez/bitshares,bitshares/bitshares-0.x,Ziftr/bitshares,Ziftr/bitshares,RemitaBit/Remitabit,dacsunlimited/dac_play,denkhaus/bitsharesx,bitshares/devshares,jakeporter/Bitshares,camponez/bitshares,camponez/bitshares,RemitaBit/Remitabit,dacsunlimited/dac_play