don't allow the history to grow too much + save_session refactoring add a mechanism that will signal a regeneration of the history file once it reaches the 150% of the HISTORY_CAP. while here refactor save_session, now it's somewhat readable.

move load session stuff to session.c

persist list of visited URLs to the disk Persist a generalized history of visited URL in history_file and try to keep it in sync during telescope usage and shutdown.

move headers to include/