Change keyboard shortcuts so they don't overwrite Polish characters

Shortcuts ctrl-alt-{a,c,e,l,n,o,s,z,x} are used to type Polish diacritical letters: ą,ć,ę,ł,ń,ó,ś,ż,ź. Now Polish people cannot write ó and ś letters, so I propose to change Open Folder to ctrl-alt-F and Save All to ctrl-shift-S instead.