Use QByteArray::{from,to}PercentEncoding when operating directly on
byte arrays.

Don't use toEncoded/fromEncoded if the final source/destination is a
QString -- QUrl's constructor and toString() are fine for that.

Change-Id: I9349c2c6a12c43b8c5a4a4fca1fa796272ca90fa
Reviewed-by: Shane Kearns <shane.kearns@accenture.com>