Proposal: Split concept of Algorithms & Strategies

[jdfergason]

Current approach:

There are portfolios and strategies. Each portfolio is assigned a single strategy.

New approach:

Class	Descrpition
Algorithm	the code that computes transactions; globally available
Strategy	a particular parameterization of an algorithm; globally available
Portfolio	a collection of transactions associated with a single user
Indicator	a numeric time-series such as MACD or Momentum

In this new formulation, Portfolio's are constructed from a collection of strategies. E.g.: assume you have defined 3 strategies ADM, PAA, and DAA.

Portfolio 1

25% $ADM
50% $PAA
25% $DAA