Refactor code for shelling out to gcc
Revert "Use tcc to aot compile instead of gcc"

This reverts commit 4c56b952ba1ebfb227e6a8c34a2567f9e4115fd7.

This didn't work on macOS :-(

From my understanding, TCC does not support building an executable on
macOS. So, we're stuck with gcc/clang for now.
Use tcc to aot compile instead of gcc
Update description in readme
Fix bug in mal_assert macro
Update mal impl and tests from offical mal repo
Add a filter function example
Print errors when executing a mal file
Update readme for building on macOS
Update list email in readme
Fix bug compiling mal inside malcc

Also add tests!

    make mal-in-mal
    make test-mal-in-mal
Add support for UTF-8 in strings

Squashed commit of the following:

commit 20537781a60474315c02b3f8aa9d397fedf954cd
Author: Tim Morgan <tim@timmorgan.org>
Date:   Wed Feb 27 08:16:10 2019 -0600

    Just set LC_ALL in Dockerfile

commit 5f94f8d012bc09ec0cb3fd4c35e9e52438c7a861
Author: Tim Morgan <tim@timmorgan.org>
Date:   Wed Feb 27 08:07:22 2019 -0600

    Set locale in sr.ht build

commit 2589e43e96ae3ae7c3d3b5c6bccd3f1d83f838ad
Author: Tim Morgan <tim@timmorgan.org>
Date:   Wed Feb 27 08:00:58 2019 -0600

    Fix editline locale for multibyte characters

commit 7f9ab03b3cf069248a2beed0b5aaf39a92e73de3
Author: Tim Morgan <tim@timmorgan.org>
Date:   Mon Feb 25 22:50:01 2019 -0600

    Allow building without editline

    I couldn't get multibyte characters to work in Ubuntu with editline. So
    I'm just disabling it for the tests.

commit ae8bc2cb8fecc1cc57cf65cc03f5e921aec21933
Author: Tim Morgan <tim@timmorgan.org>
Date:   Sun Feb 24 20:15:13 2019 -0600

    Add support for UTF-8 in strings
Use realloc instead of malloc for growing strings/vectors
Add note about contributing
Fix readme formatting and typos
Add malcc binary with aot compile option
Remove latent debugging code from step A
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