Release 0.17.0

• Implements POST/GET/DELETE operations on tags as requested in #151
• breaking change: Tag class has been completed and the type of some existing properties has been changed from object to the right type (string, Commit, etc.)
• breaking change: all methods and classes declared as obsolete in V0.14.0 and v0.15.0 are now removed. So we recommend to upgrade to v0.16 and follow warning messages produced by the obsolete attributes to fix your code before upgrading to v0.17.0.