implemented FP and BP with randomized initial weights for theta.
Ex 5 started.  parts 1 & 2 completed. working on part 3 - polynomial regression.
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implemented polynomial regression.
implemented the validation curve code for ex5.
implemented gaussian kernel similarity function.
completed processEmail.m vocabList naive linear search index lookup.

Once I finish getting this working, I will come back to implement binary
search for the vocabList search.
emailFeatures.m implemented.