chromium: Make the channel available as an attribute

Signed-off-by: Ricardo M. Correia <rcorreia@wizy.org>
chromium: Convert update.sh script to python and add support for Debian package info

Signed-off-by: Ricardo M. Correia <rcorreia@wizy.org>
chromium: Update dev and beta channels and add Debian package info

dev:  34.0.1847.3   -> 35.0.1862.2
beta: 33.0.1750.117 -> 34.0.1847.14

Signed-off-by: Ricardo M. Correia <rcorreia@wizy.org>
libpdf: Add new package

libpdf is a binary plugin distributed with Google Chrome that allows PDFs to be
opened inside the browser.

A big thanks to @PkmX for the original work which this is based off of.

Signed-off-by: PkmX <pkmx.tw@gmail.com>
Signed-off-by: Ricardo M. Correia <rcorreia@wizy.org>
pepperflash: Add new package

pepperflash is the binary Adobe Flash plugin distributed in Google Chrome.

A big thanks to @PkmX for the original work which this is based off of.

Signed-off-by: PkmX <pkmx.tw@gmail.com>
Signed-off-by: Ricardo M. Correia <rcorreia@wizy.org>