Non-standard proxy config `predix.oauth.proxyHost` should use `https.proxyHost`

[bsyk]

The configuration for using a proxy to interact with services is using a non-standard environment variable / property. This seems to be undocumented except for a comment within a config file.

Suggestion to use the standard java proxy variables:

http.proxyHost: the host name of the proxy server
http.proxyPort: the port number, the default value being 80.
http.nonProxyHosts: a list of hosts that should be reached directly, bypassing the proxy. This is a list of patterns separated by '|'. The patterns may start or end with a '*' for wildcards. Any host matching one of these patterns will be reached through a direct connection instead of through a proxy.
https.proxyHost: same as http, but for https connections
https.proxyPort: same as http, but for https connections

Reference: http://docs.oracle.com/javase/6/docs/technotes/guides/net/proxies.html