Coerce coops results to numeric, account for data results not named "data", add examples

[jsta]

126 Still unsure if I have coerced numeric results in the best way. The only consistent numeric column across all products is the second column. Here is a breakdown of the various column types:

18 col

all numeric

monthly_mean

5 col

posix-date, numeric, numeric, character, character

water_level

3 col

posix-date, numeric, character; #only for great lakes stations

daily_mean

posix-date, numeric, character

air_temperature

posix-date, numeric, character

water_temperature

posix-date, numeric, character

air_pressure

posix-date, numeric, character

conductivity

posix-date, numeric, numeric

salinity

posix-date, numeric, character

humidity

6 col

posix-date, numeric, numeric, character, numeric, character

wind

4 col

posix-date, numeric, numeric, character

hourly_height

posix-date, numeric, character, character

high_low

posix-date and numerics

currents

2 col

posix-date and numeric

one_minute_water_level

character and numeric

datums

posix-date & numeric

predictions

#no data at any station? air_gap

visibility

[sckott]

can you fix that one thing above, otherwise, looks good