change RootService to Context, add configuration

[progrium]

Context should be the top level gservice object that a Runner will create to start an application. It should be responsible for parsing a configuration file if provided, or taking/overriding with a configuration dictionary (although the code should live in the config module). This means it should also run the service factory in the configuration.

It should also own the named global services. The _main_services in Service should live in Context. Services should have a reference to the Context (all services live within a context).

ultimately, you should be able to instantiate a gservice application by creating a Context instance. For example:

app1 = Context(file='/path/to/app1.conf.py') app2 = Context(file='/path/to/app2.conf.py')

Allowing you to write functional tests of interacting applications in the same process.

[progrium]

I forgot to mention, this depends on config getting namespaces: https://github.com/progrium/gservice/issues/28

[progrium]

The basic idea of Context evolved into the top level container service Process in 0.5.0. Configuration is now represented in an object with a default global singleton that will be associated with a Process.