Update to Nexus API 3.23

Changed
- migrates from glide to go modules to be able to use recent go versions for compile
- integrates makefiles [see #2](#2)
- updates to nexus api 3.23
- fixes issue related to api changes [see #7](#7)

Add flag to set HTTP request timeout

Bump version

'v0.2.1' fixes problems with nested data structures

released v0.2.0

released v0.1.0