Renamed the key score_per_group with score_by_group (omegaup#125)

Fixing a key in order to match the name with the frontend key

This release contains the following commit:

* 8209e2e Use the new version of git2go

This release contains the following commits:

* a9a4b58 Use the Broadcaster's own TLS config instead of the global one
* 2bdee43 Do not run the benchmark loop when running on non-noop mode
* 0803771 Refactor the oneshot mode code

This release contains the following commits:

* c9b60bc Create intermediate directories for submissions
* 5e9f7b6 Allow logging to stderr

This release contains the following commits:

* 5e9cbc9 Allow saving the results of the oneshot run
* 11676ec Add a way to specify the source code for the submission instead of the JSON request
* 28f436c Allow inputs to be in a different volume than the runtime directory
* 9d50d5a Use the correct language extension for the validator file
* 18fc33e Change the expected input format of -oneshot=run

This release contains the following commits:

* 54ed73f Bail out when the meta file is malformed
* fb78c68 Make the logging of the run request failures a bit more readable

This release contains the following commits:

* 4baefb6 Add the problem alias to the input request URL
* b4278a3 Simplify the InputManager interface

This release contains the following commits:

* 818bd8b Add support for more languages
* bd5a8e8 Move the big.Rat conversion functions to go-base

This release contains the following commits:

* 395049b Fix travis build (omegaup#11)
* 3a5e0e5 Uprev Go to 1.13 on Travis

This release contains the following commit:

* fc3400d Update the omegajail invocation to match the new rootfs