prep-quizs: link to prep-quizs-name
move common functions from hello.lua to helpers
hello: no complicated calculations
move all_different to helpers
move test creating button to helpers.moon
quiz-results: add button to start new quiz
helpers: add function has_nil
test: make sure text and answers are not nil
add quiz if_list_for_range
prep-quizs-name: header one more time after data
vertical text in table prep-quizs-name
style of borders
add text "language" near language switcher
helpers: add method unpack

(table.unpack or unpack)
quiz/helpers: add function with_fakes
do not align text in center

Python code with indentation is broken being aligned
in center.
task ilfr.elif
helpers: function shuffle
model: shuffle order of tasks while creating them
finish quiz button on task page as well