Feature/remove letter accents

[klaxon1]

to resolve #363
replace certain accent / diacritic character to more of a ABC

input:

à, è, ì, ò, ù  À, È, Ì, Ò, Ù
á, é, í, ó, ú, ý Á, É, Í, Ó, Ú, Ý
â, ê, î, ô, û Â, Ê, Î, Ô, Û
ã, ñ, õ Ã, Ñ, Õ
ä, ë, ï, ö, ü, ÿ Ä, Ë, Ï, Ö, Ü, Ÿ
å, Å

output:

a, e, i, o, u  A, E, I, O, U
a, e, i, o, u, y A, E, I, O, U, Y
a, e, i, o, u A, E, I, O, U
a, n, o A, N, O
a, e, i, o, u, y A, E, I, O, U, Y
a, A

[n1474335]

Thanks very much for this, it's really useful.