Character and content-length fixes

[brettphillips05]

Added support for "complex" artist and track names that have characters which will cause issues, in addition to the occasional invalid content-length in header

1. Changed songtitle variable to include all commas in song name or title. Example fix: Earth, Wind & Fire - September.mp3 came up as Earth.mp3
2. Remove / and replace - when it exists in artists or track names because most OS does not support a file name with a slash. Example: AC/DC - You Shook Me All Night Long track name would cause script to error out because of the /. Change filename to AC-DC - You Shook Me All Night Long
3. For an unknown reason, some content-length set in the header was not correct and cURL would bomb out. Chose to --ignore-content-length in cURL, which will download the file correctly.

[covertg]

Thanks for the PR!