Support any character in filenames / note title (using encoding, substitution, etc)

Feature requests
43

This would be very useful :+1:

A character map I prefer is:

'/': '∕',  // Unicode: \u2215
':': '։',  // Unicode: \u0589
'|': '❘',  // Unicode: \u2758
'#': '＃',  // Unicode: \uFF03
'[': '〚',  // Unicode: \u301A
']': '〛',  // Unicode: \u301B
'^': 'ˆ',  // Unicode: \u02C6
'.': '․'   // Unicode: \u2024