Added vendor folder to lib folder.

It includes a function created by MATLAB to flatten a complex cell array.

lib/vendor/flatten.m

+function C = flatten(A)
+% 
+% C1 = flatten({{1 {2 3}} {4 5} 6})
+% C2 = flatten({{'a' {'b','c'}} {'d' 'e'} 'f'})
+% 
+% Outputs:
+% C1 = 
+%     [1]    [2]    [3]    [4]    [5]    [6]
+% C2 = 
+%     'a'    'b'    'c'    'd'    'e'    'f'
+%
+% Copyright 2010  The MathWorks, Inc.
+C = {};
+for i=1:numel(A)  
+    if(~iscell(A{i}))
+        C = [C,A{i}];
+    else
+       Ctemp = flatten(A{i});
+       C = [C,Ctemp{:}];
+       
+    end
+end
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