added a test for nesting. Disabled it as it turns out that current Tree impl. does not support it
introduce a .kids array (instead of .inner)
root function now returns a node (rather than an array)
transition to a more formal grammar
support nesting by moving to a shift-reduce machine
clean up
get rid of dead code
rename/extract methods: shiftOrReduce(), accumulate()
consolidate unneeded code
error reporting
use an existing markdown library
herokify