Clash with Matlab symbolic tool box function names.

[JBurniston]

After adding CVX to my path, calling the sym.m function from Matlab's Symbolic Math Toolbox produces the following warning. The "easiest" fix will be to rename CVX's internal sym function.

Warning: Class 'sym' is defined in a class folder and takes precedence over a
function with the same name that is earlier on the MATLAB path. In a future
release, class 'sym' will no longer be given precedence.