Update README.md

Update README.md

updating to build command in script

updating build instructions to specify Node 6

using specific versions of libs

try/catch on midi events

updating splash links and style

updated links to tf and magenta

small copy changes and noting which node.js version to use

load fewer audio files when the screen is smaller

copy changes

making prediction path relative

about and splash screen styling

backend uses attention_rnn now

removing print debugging