WIP
Add ability to override call/2 for per controller error handling
Ensure temp project path does not exist deleting it prior to invoking Phoenix.New.run.
Resolve conflicts
Enhance error handling with option for custom handler

Allow custom `page_controller` to be configured on Router , where `not_found/2`
and `error/2` actions can defined for custom 404 and 500 pages/handling.

Add `catch_errors` Router config to optionally disable errors being caught.

Add `debug_errors` Router config to optionally show Phoenix's 404/500 debug pages
Improve moduledocs
Update template config for new options
Add default 400/500 pages to template
Document error options and handling
Better explain error handling
Add example of catching errors at Controller layer
Bump outdated docs
Merge pull request #295 from pap/ensure_tmp_file_does_not_exist

Ensure temp project path does not exist prior to invoking Phoenix.New.run
Do not log static assets. Close #299
Rename page_controller to error_controller
Add tests for list-based messages
Make tests pass closes #301
Remove deprecated function
tidy code
fix truthyness test