Added initial Black-Litterman Code

BL.m - Added function template for Black letterman
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Black_litterman_specifics.m - Added risk aversion coefficient  equation
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capweights.m - Added function that takes in market caps
and returns the relative weights of each asset
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getStockInformation - Imported function created by Ted Teng
which allows for usage of other fields(such as market cap)  in Yahoo
finance
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main.m - Added function call to retrieve asset weighted by market caps
(to be moved to Black-litterman function)

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marketcap_string_to_num.m -created function to convert
strings such as 1.13B and 3.455M to their appropriate numerical value
replacing B and M with the corresponding number of zeros
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retrieve_data.m - Added extra parameter(market_caps),
temporarily changed program to iterate over 4 assets(in order to save
time)

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