bash script improvements

- bash_startup improvements (seeing a performance improvement of about
  36ms in parsing the default.ftcommands, also removes external calls to
  sed)
  - use parameter substitution instead of splitting with the IFS when
    reading default.ftcommands
  - escape quotes using parameter substitution instead of sed
  - replace sed in trim with parameter substitution
Fixed a segfault when waitpid returned 0
Update about dialog credits
Merge branch 'master' of https://github.com/jmittert/finalterm
Update about dialog credits
Fixed Issue #338, needed to to use nullglob.

'*' expands to itself if no expansions could be made, overriding every other file in ls_output.
Hidden files also have semantic menus now.
Update about dialog credits
Fix #187 by removing / readding menu_button on mouse_enter/leave events
Merge branch 'Iss187' of https://github.com/arkocal/finalterm
Update about dialog credits