[Minor] moved .png into .\fig subfolder

Signed-off-by: Oleg Komarov <o.komarov11@imperial.ac.uk>
[Add] unid2permno

Signed-off-by: Oleg Komarov <o.komarov11@imperial.ac.uk>
[Change] importCsv refactoring #01

Signed-off-by: Oleg Komarov <o.komarov11@imperial.ac.uk>