refactor the naming within plugin new generator

Having a method called `full?`, which checks on :full and :mountable
is very confusing. I renamed `full?` to `engine?` and created a `full?`
method that only checks the `:full` option
fix img width in guides
Merge pull request #8770 from goshakkk/guides-img-fix

Fix img width in guides
Merge pull request #8263 from senny/refactor_plugin_new_generator

refactor the naming within plugin new generator
These are already required through AS/rails

* dependencies/autoload
* concern
* deprecation
Missing require
Fix error when assigning NaN to an integer column

Also covers any non-castable case by returning nil, which
is in-line with the intention of the former implementation,
but covers the odd cases which respond to to_i but raise
an error when it's called, such as NaN, Infinity and -Infinity.

Fixes #8757
Merge pull request #8781 from trisweb/tristan_8757_integer_column_nan_error_fix

Fix error raised when assigning NaN to an integer column
fix for rbx

Rubinius returns a boolean after such assingment
response = (_, headers, body = @app.call(env))

see https://github.com/rubinius/rubinius/issues/2117

get rid of a local variable
Merge pull request #8782 from tank-bohr/master

doesn't work with rubinius
refactor Journey::Routes

* prefer do-end for multiline blocks
* prefer or-equals over returns with checks
Merge pull request #8783 from goshakkk/refactor-journey-routes

Refactor Journey::Routes
Needs to reset SchemaMigration first, or the tests fail in sqlite3
Namespace HashWithIndifferentAccess
Reduce number of Strings a bit
Fix failing test under sqlite3
return multiple assingment and response variable
refactor DebugExceptions by combining two conditionals into one
Merge pull request #8785 from goshakkk/refactor-debug-exceptions

Refactor DebugExceptions
Merge pull request #8787 from tank-bohr/master

masgn and response variable