Fix warnings in tests

[kiudee]

We have many warnings in the tests, since we accidentally escape characters in the docstrings.

Example:

cs-ranking/csrank/core/cmpnet_core.py

Lines 69 to 74 in 6c4c30c

	"""
	Construct the CmpNet which is used to approximate the :math:`U_1(x_i,x_j)`. For each pair of objects in
	:math:`x_i, x_j \in Q` we construct two sub-networks with weight sharing in all hidden layers.
	The output of these networks are connected to two sigmoid units that produces the outputs of the network,
	i.e., :math:`U(x_1,x_2), U(x_2,x_1)` for each pair of objects are evaluated. :math:`U(x_1,x_2)` is a measure
	of how favorable it is to choose :math:`x_1` over :math:`x_2`.