Fix OS X keymaps

9 conflicts:

Important ones for really used commands:

	Conflict in ctrl+shift+up ('select_lines' vs 'headline_move')
		changed -> alt+shift+up (also, ctrl+up -> alt+up)
	Conflict in ctrl+shift+down ('select_lines' vs 'headline_move')
		changed -> alt+shift+down (also, ctrl+down -> alt+down)
	Conflict in shift+tab ('prev_field' vs 'smart_folding')
		changed -> alt+tab
	Conflict in super+shift+f ('show_panel' vs 'magic_footnotes')
		changed -> alt+shift+f

Less important or desired (not changed):

	Conflict in tab ('commit_completion' vs 'smart_header')
	Conflict in super+shift+b ('build' vs 'strongemphasis')
	Conflict in super+shift+i ('show_panel' vs 'emphasis')
	Conflict in super+shift+t ('reopen_last_file' vs 'merge_cells_left')
	Conflict in enter ('hide_panel' vs 'smart_list')