model, first implementation of Sequence
implement Sequence as table, not as function
add gitignore
implement function Sequence.to_atgcn
Sequence: clean text (keep only ATGCN)

activate test for ATGCN
add tests of sequence text cleaning
move sequence test to spec/model
rename test "sequence" to "model.sequence"
directory util, function util.split
npge.util.unpack = unpack or table.unpack
Sequence: add methods extracting data from name

Methods genome, chromosome, circularity
gitignore *.out

luacov.stats.out
add test for Sequence.to_atgcn
test Sequence:at
change code for luacov

luacov thinks that the following lines
of code are not covered:

*   return a
        :foo()

    local f = function()
*       return 1
    end
add luacov config
Sequence: add arguments type assertations
Sequence:type() = 'Sequence'
test Sequence:size
change implementation of Sequence

Do not create a metatable for each instance.