Move leaflet-rails (map embedding) into gaslight site from training, locking version due to bug in 0.7.4

Error in 0.7.4 is "No value provided for variable {s}, similar to issue at https://github.com/Leaflet/Leaflet/issues/1871, not present in 0.7.3
Fix embedded map on course show page
Load blog engine application helper

I have no idea how this is working in production but is no longer 
working on my machine.
Change precompiled asset path from training_app
Move alignment class out of blog
First pass through on new style for /blog
Design tweaks for mobile
Separate post and post-preview style
Reposition footer
page_path helper is not available in the engine
Adjust CSS class for posts on index page
Tags are no longer visible on post show page
Remove generic .content class from blog
Center author on post page