Host specific settings

[davidized]

Determine how to deal with host specific settings.

I'm leaning toward subdirectories with separate install configuration files since I don't have a lot of variation in configuration of machines instead of a full blown dotfiles_local repo as suggested by Anisha Athalye

[davidized]

Started work in 337043f. Install script now can take an argument which specifies the host to use. Still need to do some work:

• - Check if config file exists
• - Global config file(s) - i.e. OSX specific config that could be shared between uranium and curium; a global config that would work for OSX and Linux