Prevent sending symbols to api that can't be found by yahoo

[melissaSchmidt0302]

A lot of symbols that are send to the api are not being found by the yahoo library. Maybe exchange the library of the symbols to provide working symbols or find another solution to prevent sending symbols to the api that can't be processed.

[hlavacek]

for now I would wait until the library is updated, there isn't an easy way to find out the symbols that are supported by the API. + also fixing the error handing might help so focusing on that first.

[hlavacek]

I've also enhanced the error handling now, so it should display which symbols were not successful in being sent to yahoo finance API