This change adds the mocha-teamcity-reporter which outputs the running
tests in a special format that TeamCity can interpret. This allows TC
to show which tests run as well as the number of tests run.
Also refactor some of the build scripts to use functions.
Note that we had to explicitly add `--check-coverage=false` (which is the
default) to get successful builds when we run on TC.
The package subfile description field is never really used in the
end-user apps. As it is meaningless metadata, we'll make it fully
optional, and start to remove all references in the designers and
compilers.
TODO: For packages targeting Keyman 18.0+, we should consider removing
the description field altogether from the subfiles.
This requires a significant refactor to the compiler interfaces to allow
for asynchronous filesystem and network access. For now, only kmc-copy
uses the asynchronous interfaces, but over time we may try and
consolidate them where other compiler modules find them useful. This
adds a big set of unit test fixtures to avoid network instability in
tests (the fixtures can be regenerated by setting environment variable
`TEST_SAVE_FIXTURES`).
