Update pa6.cpp

Filled in toLowerCase(str) and removePunctation(str) methods and modified removeCapsAndPunct(str) to use them. Made a few changes in removePunctuation(str) - untested as of yet.
Merge pull request #1 from CliftonAncell/patch-1

Update pa6.cpp
Update pa6.cpp

updated removePunctuation(str)
Update pa6.cpp

fixed mistake in removePunctuation(str)
Update pa6.cpp
Merge pull request #2 from CliftonAncell/patch-1

Patch 1
Merge pull request #1 from michaelangel/master

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