Hob: allow users to setup the proxies

Hob: allow users to setup the proxies

This patch is to read the proxy variables such as all_proxy, http_proxy, https_proxy, ftp_proxy, GIT_PROXY_HOST, GIT_PROXY_PORT, CVS_PROXY_HOST, and CVS_PROXY_PORT from the bitbake server, show them on the Settings dialog for users to change and set proxies for the build.

(From Poky rev: bbef66e4005def54d70d3720ec131fa7edc22e2a)

(Bitbake rev: 66c63167cd139706100bfa35eb4ca66c98407615)

Signed-off-by: Shane Wang <shane.wang@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>