Ensure the client gracefully handles unrecognized currency codes

[rmisio]

In all the myriad of ways the client is given a currency by the server, ensure that if the client is given an unrecognized code, it appropriately handles the situation. In many cases, this could be as simple as an alert message which may block off dependent functionality. What we want to avoid is the client bombing on an exception and being completely unusable.

[placer14]

FYI, we introduced a code pattern to begin reigning this problem in on the server side.

[jjeffryes]

FYI, we introduced a code pattern to begin reigning this problem in on the server side.

@placer14 If you mean the code to handle the bug where no currency code is given, that's a different issue. This is if the server provides a code the client doesn't know how to handle, for example if a rogue node somewhere adds a new coin.