rfm: server to expose classes
rfm: need to validate user for the call
rfm: fix typo
rfm: blocks all methods except those should be exposed
rfm: refactor methods blocking
rfm: tag writer for mp3
music: upload binary to client
rfm: secure tag writer and reader
issue_150: specify topfolder when start server, cleanup require, random security key
issue_153: simplify interaction with server. Only expose 1 class