Revert "Delete gradientDescentMulti.m"

This reverts commit 2119f95a45aceae47b7c48a0c4c6d4e2e15bd39b.
Revert "Delete normalEqn.m"

This reverts commit 761a6a7bb9aa8edf01415fc2a91ae12af1f7db72.
Revert "Delete lr_multi.m"

This reverts commit 498db9d0ab3358e4422ddd6d21686b907daa3c8a.
Revert "Delete featureNormalize.m"

This reverts commit 539f53a821d15c85803441cc18c01bacb6d5a877.
Revert "Delete data2.txt"

This reverts commit 28ef3c0732599c03d4fb4115894288c6324353ac.
Revert "Delete computeCostMulti.m"

This reverts commit f344fce22b88dc84b4f21448abac975ed83e8f62.