Less abuse of methods, safer memory management

Re-instated dockerfile, removed legacy tests

Merge pull request githubexporter#53 from AdamSlack/master

Update Golang docker image to golang:1.14.8-stretch

update version

Merge pull request githubexporter#48 from adebasi/master

Allow to specify no targets

Merge pull request githubexporter#18 from infinityworksltd/rate_fix

Fixes for installations without rate-limiting

Merge pull request githubexporter#15 from infinityworksltd/v2

V2 Rewrite..

Merge pull request githubexporter#14 from alexellis/patch-1

Fixes githubexporter#13

Added private repo support