Release v0.13.0

• Fix crash when padding before widechar (#540)
• Do not lag when reading input too fast (#536)
• Session name optional in attach command (#542)
• Fix build on platforms with TIOCGWINSZ / ioctl() integer type mismatch (#547)
• Fix(ui): session mode should be disabled in locked mode (#548)
• Add option to start in arbitrary modes (#513)
• Attaching to a session respects the default_mode setting of the client (#549)
• Add option to specify a color theme in the config (#550)
• Fix config options to not depend on simplified_ui (#556)
• Don't rename unnamed tabs upon deletion of other tabs (#554)
• Add layout to disable the status bar (#555)
• Significantly improve terminal pane performance (#567)