Properly decode UTF-16 string

When unicode string is UTF-16, properly decode it.

Fixes #8

Signed-off-by: Michal Čihař <michal@cihar.com>
Document change

Signed-off-by: Michal Čihař <michal@cihar.com>
Use correctly size_t for iterating over length

Signed-off-by: Michal Čihař <michal@cihar.com>
This is really an unsigned char

Signed-off-by: Michal Čihař <michal@cihar.com>
Fix EncodeUTF8QuotedPrintable to match EncodeUTF8

This is really ugly as these should rather share the code...

Signed-off-by: Michal Čihař <michal@cihar.com>