SQLITE with device config closing json file

This release is a minor addendum to the SQLITE branch that closes a JSON config file after constructing device_config --- see #105 and #115 (also #114).

SQLITE backend

This version brings us one step closer to a microservice architecture with using SQLITE as a temporary storage of sampled values. This completely removes the in-memory dependence of sampled values, which means that the sampler and the submitter now safely can run in separate processes/environments as long as they have access to one common SQLITE file.

Timeouts galore

This is a small improvement over the previous version, where we explicitly configure timeouts for every requests call.

startup sysinfo and os info

Merge pull request #107 from pgdr/os_release_sysinfo

added /etc/os-release to sysinfo

Startup sysinfo

Merge pull request #104 from pgdr/sysinfo

added sysinfo for logging on startup

TCP and service restarts

Merge pull request #103 from pgdr/close-connection

close connection or keep-alive

Log POST exceptions

Merge pull request #86 from pgdr/log-if-not-201

WIP Changes to post_value and post_stack

UpdateX

Merge pull request #80 from joakim-hove/update-bug

Make sure the git_ref is checked

Git follow + update fix

Merge pull request #72 from joakim-hove/doc-updates

Doc updates

Post median

• Post median.
• Refactored client to be more testable.