Switch to using mikeal/request to gain proxy support

[tauren]

Replaced https.get with request, added support for removing config settings, and passing proxy config through to endpoints.

Dependent upon the latest request package which includes automatic proxy support based on environment variables.

[guybedford]

Awesome! This looks great. Is it not possible to convert the proxy config into environment config like we discussed, or is the no_proxy option still a blocker for this?

[tauren]

Note that this does NOT include the following:

• jspm config proxy settings are not used and do not override environment proxy settings
• no_proxy environment variables are ignored