return lowest_ask and highest_bid order volume

[crazybits]

this PR related to discussion of #2001 to return more useful data in ticker.

before change

{
    "id":3,
    "result":{
        "time":"2020-04-28T15:22:24",
        "base":"CNY",
        "quote":"BTS",
        "latest":"0.224489795918367346",
        "lowest_ask":"0.224634524247316643",
        "highest_bid":"0.224529552603249653",
        "percent_change":"-0.01",
        "base_volume":"386624.9459",
        "quote_volume":"1722080.6122"
    }
}

after change

{
    "id":3,
    "result":{
        "time":"2020-04-28T15:22:24",
        "base":"CNY",
        "quote":"BTS",
        "latest":"0.224489795918367346",
        "lowest_ask":"0.224634524247316643",
        "lowest_ask_base_size":"304.8588",
        "lowest_ask_quote_size":"1357.13244",
        "highest_bid":"0.224529552603249653",
        "highest_bid_base_size":"2288.6050",
        "highest_bid_quote_size":"10192.88986",
        "percent_change":"-0.01",
        "base_volume":"386624.9459",
        "quote_volume":"1722080.6122"
    }
}

[abitmore]

Thanks.

[abitmore]

This change is quite small, perhaps rebase onto hardfork branch then we can add it in the 4.0 release.

[abitmore]

If not rebased onto hardfork, this PR will be merged after Github Auto-Build got fixed (#2112).

[crazybits]

If not rebased onto hardfork, this PR will be merged after Github Auto-Build got fixed (#2112).

to many conflicts if rebase these changes to "hardfork" branch, to make it easier, i could close this PR and cherry-pick the changes to hardfork branch, then raise PR again to hardfork branch, it that fine?@abit

[oxarbitrage]

That is fine @crazybits

[crazybits]

new PR has been raised #2166