Add unit tests for internal retry decorator
Add support for socket timeout retries in scc

Fix #48
Add support for SSL error retries in scc
Refacotr TestInternalRetries to run series of tests on each class
Add test calss for GithubRepository __init__ method retries
Decorate GitHubRepository get_pull, get_issue and get_pulls methods

Implement corresponding unit tests
Add internal retries test for GHManager.get_organization()
Decorate GHManager.get_login()
merge master -D org -I include -E exclude: PR 119 (Add unit tests for internal GH API call retries)