Restructures the test suite as a proper El vessel with manifest.el and
src/ layout, eliminating the bash run.sh harness. CI runs the suite with
two commands: `cd tests/suite && elb && ./dist/el-tests`. Exit code is
the fail count (0 = all pass).
163 test cases across 7 modules: string (52), math (13), json (26),
state (11), time (25), fs (16), collections (19).
Will Anderson