- replace bools for internal non-persistent binary states with an uchar
- do not store path to session, derive from config path in tmp buffer
- program option to load session is not `-s`
- remove auto-stored session "@" on restore
- minor help update
* Initial commit of sessions implementation
* Reduce code duplication
* Move load session to program flag -e
* Fix context initialization problem when loading session
* Add pinned directory to session and reduce session file size
* Make load_session print an error if exists and few minor adjustments
* Refactor session's file structure
* Initialize required structures in load_session before loading
* Add load session dynamically, restore last session, and extra fixes
* Fix indentation
* Add sessions documentation to man page
* Update fish completions with sessions and make some improvements
* Move to single keybinding session management and add help info
* ESC when asked to insert session name behaves better
* Add sessions completion for bash
* Remove pinned dir from session and minor code refactors