Create Market: Replace "trading fee" with "taker fee" and re-define "maker fee" to be independent

[thinkloop]

Currently we have:

trading fee: % of total value of trade (ie 2%)
maker fee: % of trading fee (ie 50%)

We are simplifying this paradigm so that a taker fee and maker fee can be specified more independently of each other, and dropping the concept of trading fee from the ui. In the market creation process, the fee inputs should be:

taker fee: % of total trade value (ie 2%)
maker fee: % of total trade value but not higher that 50% of taker fee (ie 1%)

The only limitation is that the maker fee cannot exceed half of the taker fee. Ex: if taker fee is 3% maker fee can be between 0 and 1.5%.

These fees will also be passed into augurjs for the createMarket functionality, so this issue is dependent on this one: AugurProject/augur.js#85

And the related UI work: tinybike/augur-ui-react-components#36

[stephensprinkle-zz]

PRs #675 + AURC #42 resolve this issue -- closing.