[Caminol10n] RelNotes translated to Portuguese

[Stefano]

I've finished the translation of Release Notes of Camino 1.5.1 and
1.0.6. Since 1.0.x series has been translated to pt-PT I've translated
the 1.0.6 Release Notes file to both pt-BR and pt-PT. However, for
Camino 1.5.1 I've just translated to pt-BR since this version does not
contains a pt-PT localization anymore.

"Release Notes for Camino 1.5.1" in pt-BR is available at
<http://web.omnidrive.com/APIServer/public/GD0mpU67tH02oBAQEkdxsKwO%2Fv1_0_5_1>

"Release Notes for Camino 1.0.6" in pt-BR and pt-PT is available at
<http://web.omnidrive.com/APIServer/public/GD0mpU67tH02oBAQEkdxsKwO%2Fv1_0_6>

Stefano