Lecture 4 for next year

[yoavram]

Changes that should be made for next year. I suggest to remove the CSV format entirely - it will be done in later classes.

[soungalo]

• In general, the lecture is too packed. Maybe move regex to another lecture.
• The file-parsing exercise is too integrative. Should be easier and more specific. Split to two exercises: one for writing files (optional) and one for writing a parser function.
• When teaching the regex syntax, show examples on natural text rather than DNA (too difficult to see why patterns are found/not found in DNA strings).
• Show how to parse files using regex.