added energy market service functionality

[can7huang]

added energy market service functionality. Run energy_market_service.py

[hlngo]

@can7huang For integration test, we need to reference all files by using absolute paths instead of relative paths. Can you make the following changes:
Under your init, add:
self.base_path = dirname(abspath(file))
For ALL csv files you reference to, change:

price = np.genfromtxt('CAISOApr2016Hourly.csv', delimiter = ',' )
to
price = np.genfromtxt(join(self.base_path, 'CAISOApr2016Hourly.csv'), delimiter = ',' )

Thanks.

[hlngo]

@can7huang I will do it since it's quite simple