Manual grouping of stocks for graphing

[ConradSelig]

Currently there are two options for graphing, either all of the stocks in the portfolio are put on one graph, or they all have separate graphs.

Manual grouping of stocks should be implemented so the user can pick and choose which stocks are put on the same graph.

Group names should be restricted as little as possible, allowing for both numeral and text group names.

The number of groups available to the user should also not be limited.

Stock groups should also NOT be mandatory, meaning the user should not have to specify a group for all stocks in the portfolio. Stocks without a group should follow the "independent_graphs" option.