`get_cumulative_confirmed_cases_on_day()` and the like don't take into account blank days

[agarny]

If we do something like:

import moh_data.main as md
data = md.Basic()
data.get_cumulative_confirmed_cases_on_day(0)

then, we get 1, as expected. However, if we then do:

data.get_cumulative_confirmed_cases_on_day(1)

we get 2 while it should still be 1 since the first confirmed case was on 26 February while the second one was on 2 March. In the same way, if we do:

data.get_cumulative_confirmed_cases_on_day(1)

we get 4 while it should still be 1.

In other words, get_cumulative_confirmed_cases_on_day() doesn't into account the fact that some days may not have had confirmed cases.

[mahyar-osn]

Oh yes - I didn't realize that I should leave gaps between each date that's available in the MoH data (duh!). Since the data only contains the dates for which there have been cases since Feb 26th, it does not account for the dates in between. Anyway will fix this and make a new PR.

[agarny]

Thanks @mahyar-osn. Otherwise, in your FindExcelFile class, you are doing:

url_reader = urlopen(self._cases_url)
try:
    html = url_reader.read().decode('utf-8')
finally:
    url_reader.close()

but this is not needed.

[mahyar-osn]

You're right. I missed that part after I started using BeautifulSoup! Will remove it in the new PR too.