interpolate design mtx with nearest neighbor
adding the scaling of the design matrix
Some documentation on the t-test computation
Adding better compatibility with numpy 1.4
Adding JB's edits and some introduction
A little bit of cleaning on the latex bits
NF: add notebook exploring R formula
NF: added 3 way interaction deficiency explanation

Jonathan pointed out that 3-way interactions will often be rank
deficient.
NF: a * b * c example

I didn't grasp that * expands all the intermediate terms.
Adding exporing_r_formula ipynb
reverting to the upstream version of the ipynb after messing up
Some small additions - up to Factors section
STY: a few typos
adding a .gitignore
added some more
Merge branch 'r_formula_smallstuff' of github.com:jbpoline/nipy-notebooks into r_formula_smallstuff

* 'r_formula_smallstuff' of github.com:jbpoline/nipy-notebooks:
  added some more
  adding a .gitignore
  STY: a few typos
  Some small additions - up to Factors section
  reverting to the upstream version of the ipynb after messing up
  Adding exploring_r_formula ipynb
  Adding exporing_r_formula ipynb
  NF: a * b * c example
  NF: added 3 way interaction deficiency explanation
  NF: add notebook exploring R formula
  A little bit of cleaning on the latex bits
  Adding JB's edits and some introduction
  Adding better compatibility with numpy 1.4
  Some documentation on the t-test computation
  adding the scaling of the design matrix
  interpolate design mtx with nearest neighbor