Added 3rd hint is vowels option

Fixed #46 
Fixed #47 
Fixed #48 

caveat:
All accents are removed, and will never be displayed in hints. This is becuase an accented character takes 2 indexes in a string

These chars are not masked:
" _ = + & % $ # @ ! ~ ` [ ] { } ? . , < > | \ /

These chars can be folded:
á,é,í,ó,ú,ü,ñ