v3.3 release (SathyaBhat#59)

* fix: user_id error & support for playlist url with or without userid

* prepare for release

bump up to v3.0, we're going python 3.0+ only (SathyaBhat#48)

v2.6: add support for config file for defaults

v2.5 - download using spotify playlist URL

v2.4 release

release 2.3

bump up version