Print backtrace when compilation fails

[patrobinson]

When a template fails to compile it's common to get an error like:

Executing apply on samson-db in us-east-1
StackMaster::TemplateCompiler::TemplateCompilationFailed Failed to compile /Users/matt/Documents/GitHub/our-samson/aws/templates/samson_db.rb.
 Caused by: NameError uninitialized constant #<Class:0x007f850a560748>::Sparkleformation 

Which is quite unhelpful to understand where the error occurs. This PR makes two changes to combat this:

• When we do catch an exception, print the error and backtrace.

[petervandoros]

LGTM 👍

[stevehodgkiss]

Only catch StandardError. NameError and SyntaxError will throw an exception and not get caught

StandardError is the default for rescue so this isn't changing which errors are being caught (if that was the intention).

[patrobinson]

@stevehodgkiss you're right. StandardError will catch NameError but not SyntaxError. I'm not sure what we want to do so I'm just going with printing a backtrace

[stevehodgkiss]

👍