Added the following functions to taInvoke.cpp with associated paths to source files to mexOpts.txt: MAVP,MAX,MAXINDEX,MEDPRICE,MFI,MIDPOINT,MIDPRICE,MIN,MININDEX,MINMAX,MINMAXINDEX.

Replaced README TAINVOKE.txt with README TAINVOKE.md

Signed-off-by: Mark Tompkins <mtompkins@openAlgo.org>