Release 1.5, adding OSC 133 support

What's new

• Support for OSC 133 escape sequences.
• When OSC 133 B codes are issued, mark prompt as field, so commands like kill-whole-line or meow-line work properly when on a prompt
• Commands such as mark-defun or next-defun can be used to navigate through older command outputs
• Build index for imenu to navigate through older prompts and their output (works well with breadcrumb)
• mistty-next-input/mistty-prev-input now go to the beginning of user input
• Option mistty-allow-clearing-scrollback lets reset clear the whole buffer

What's fixed

• Fix issue #47: Sync marker moved by ESC [ 2 K used on same line.
• Fix issue #45: Resize terminal when nonselected window is resized.
• Fix issue #12: Read does not respect backspace under Mac OS

Full Changelog: 1.4...1.5