Facility from buffer

[kirubaspace]

This fixes https://github.com/goatshriek/stumpless/issues/385

Make sure that your pull request follows the guidelines specified in the Guidelines for Contributing.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (c512e68) 91.78% compared to head (e014b45) 91.79%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## latest #387 +/- ## ======================================= Coverage 91.78% 91.79% ======================================= Files 44 44 Lines 3774 3776 +2 Branches 497 497 ======================================= + Hits 3464 3466 +2 Misses 216 216 Partials 94 94 ``` | [Files](https://app.codecov.io/gh/goatshriek/stumpless/pull/387?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Joel) | Coverage Δ | | |---|---|---| | [src/facility.c](https://app.codecov.io/gh/goatshriek/stumpless/pull/387?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Joel#diff-c3JjL2ZhY2lsaXR5LmM=) | `100.00% <100.00%> (ø)` | |

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[goatshriek]

Make sure that you can get full coverage: either add a test for the code branch that is uncovered, or refactor so that it is not needed.

[goatshriek]

Thanks very much for putting this together!