createNewMarket arguments

[TvrtkoM]

If createNewMarket function gets changed in future please consider using options object instead of individual arguments:

e.g. something like createNewMarket(signer, title, options) instead of createNewMarket([endless list of arguments]).

[morkeltry]

This change was implemented but seems to have (24th May) been reverted somehow somewhere down the line.
Reopening issue, propose (breaking change) to change out existing createNewCategoricalMarket(signer, title,description, oracle, end, creationType, categories, callback?) for object paramaters, so that the first form will cease to work.

This issue replaced by (#81)