Adding tped functions

io now has 2 private functions and accessible save-tped function

h5 has function that calls function in io.

Support for genetic distance and snp id
Added test, fixed bug with lack of str()

Tests for file creation and num lines is correct
Slightly unsure how to handle file handles being passed in, not paths
Updated with changes from AM

- removed return None
- better handling of tuples
- ref/alt in hdf5 uppercase
Adding setUp method

So that namespace is not polluted
Reordered logic for samples if None

Now no copies of array created unnecessarily
Merge pull request #60 from hardingnj/addtped

closes #35