add day3 material
add more day 3 material
add hw2
add hw3
add hw4
add code for day 4
add lab material for day 5
add material for day 6
add hw5
add code for day7
add hw 6
add code for day 8
add code for day 9
add hw 7
add lab code for day 10
add txt file to read from
merge upstream