Added Security.SetMarket

[StefanoRaggi]

This enables users to download, convert and use data from providers currently unsupported by Lean (e.g. Oanda, Alpari, etc.)

The location of the custom data is, as usual, \data-folder\security-type\market\resolution\symbol...

Usage example, in algorithm Initialize():

AddSecurity(SecurityType.Forex, "EURUSD", Resolution.Tick);
Securities["EURUSD"].SetMarket("Alpari");

[jaredbroad]

Cool thanks @StefanoRaggi :) We're actually just about to clean that up now to merge "Country Code" and "Liquidity Provider" into one concept -- "Market". This way we can minimize the variables and switching and its a more generic idea.

Give me 30minutes and I'll commit the new Markets build.

[StefanoRaggi]

@jaredbroad Ok. I'll wait and adapt the code to the new commits.

[jaredbroad]

Thanks for the PR @StefanoRaggi, its a good addition