#8 Improved proxy handling for ant build script

[Torsten Schlabach]

This relates to bug #1327626:

The attached patch (diff of build.xml against version
5.0.1) makes sure that not only proxyhost and proxyport
but also proxyuser and proxypassword are set by the
<setproxy> ant task.

Also the detection if a proxy is to be used at all has
been changed, to there is no need for the has.proxy
property in ../.ant-global.properties anymore.

Instead a file ../.ant-proxy.properties has been
introduced that can contain the properties

proxy.host
proxy.port
proxy.user
proxy.password

In case that file exists and defines the properties,
they will be used. In case the file does not exist, the
build.xml script will check the environment for

PROXY_HOST
PROXY_PORT
PROXY_USER
PROXY_PASSWORD

and use them.

In case neither the file is there nor the environment
variables are set, no proxy will be used.

[Torsten Schlabach]

Diff of build.xml against version 5.0.1