is_market_open bug

[ishankgoel]

function is_market_open return true even if is holiday today. Problem is in the line: https://github.com/aeron7/nsepython/blob/6f3a7285d39e874d6b677df0286a966e1982e56f/nsepython/rahu.py#L909

This only checks for first holiday from the nse_holidays() json result and return True by checking only the first. It should be continue here to check for the next holiday date and a final return true at the end of function.