C-strings prefixed to commands (modified by the Makefile), the helper
functions are now standalone scripts in the helpers/ dir, which gets
added to "$PATH" when running bb.
things a lot less ambiguous. Also removed the default marks created in
bbstartup.sh and ensured that `$XDG_DATA_HOME` and `$XDG_CONFIG_HOME`
always get set as environment variables.
functionality for mouse clicking/dragging/left clicking/middle
clicking/double clicking and to have more standardized behavior for key
names and better handling of key modifiers (Ctrl, Alt, Meta, Shift).
Also moved Ctrl-c and Ctrl-z to custom key bindings with (bb +kill and
bb +suspend). Mouse clicking is now also handled in key bindings.
