Combine the install generator and app generator

[seancdavis]

Let's do the basics in one fell swoop. The important thing here being not forcing into anything. Leaving other gems out of this, and keeping our utility classes behind the curtain.

So, install will:

• Add the config file
• (We're ditching the settings file, but will provide a simpler way to get at Rails' secrets.)
• Add the skip generators option, unless told not to

[seancdavis]

After looking through this, there wasn't much that would help generically. So I killed the app generator and will rewrite the useful pieces in more appropriate settings (we have issues already for those). The only thing I kept was an option to tell the install generator to add that config block that skips Rails generating all the helper files when using a rails generator.

Additionally, I'm thinking that the options we have ATM in the Cambium configuration are going to quickly become obsolete. I want to keep the config around for a bit though, because I think we'll find some benefit from it before v2.0 is ready.