reading list: add "Coding Interviews"

Add "Coding Interviews" by Harry He.

Signed-off-by: Christoph Jaeger <email@christophjaeger.info>
reading list: add "Programming Interviews Exposed"

Add "Programming Interviews Exposed" by John Mongan et al.

Signed-off-by: Christoph Jaeger <email@christophjaeger.info>
reading list: mark "Programming Interviews Exposed" as currently-reading

Signed-off-by: Christoph Jaeger <email@christophjaeger.info>