fix duality gap calculation
rename p and k into iteration
add tests for frank wolfe pickling and batch version.
fix:  make test easier so that we can use qpbo
Remove redundant constraint in LP construction, get rid of GLPK
dependency!
DOC add reference to papers to learner docs.
DOC correct shape of y in EdgeFeatureGraphCRF. Closes #98.
FIX remove debugging output!