fix NumberFormatException problem

[ILevchugov]

fix NumberFormatException problem from https://github.com/sealedtx/java-youtube-downloader/issues/110

Used where necessary method with Long.parseLong implementation

[sealedtx]

@ILevchugov appreciate your work Maybe you should also change int to long here: https://github.com/sealedtx/java-youtube-downloader/blob/bc6d37a040cbf679ca0b68c05a532aa32ee5a18a/src/main/java/com/github/kiulian/downloader/parser/ParserImpl.java#L391-L392

And is it possible to find some testcase for request to be sure that #110 is resolved?

[ILevchugov]

@sealedtx appreciate for your feedback, I've done it.

[sealedtx]

@ILevchugov oh, my bad, I believe we can keep videoCount as integer to avoid further validation videoCount < Integer.MAX_VALUE, and most likely there won't be ever a playlist containing more than 2 billions videos, sounds unrealistic for me (and anyway it won't work with ArrayList) So lets revert those changes and keep videoCount as integer but viewCount as long and than I'll merge it

[sealedtx]

@ILevchugov don't forget to change viewCount to long

[ILevchugov]

@sealedtx done)

[sealedtx]

great, thank you very much