Updates to make rails 4 happy with minitest 5:

+ Namespace changes, overhaul of runners.
+ Internal ivar name changes
- Removed a logger globally applied to tests that spew everywhere?!?
+ Override Minitest#__run to sort tests by name.
+ Reworked testing isolation to work with the new cleaner architecture.
- Removed a bunch of tests that just test minitest straight up. I think these changes were all merged to minitest 4 a long time ago.
- Minor report output differences.
tweak dependencies
oops. I should have only required minitest, not minitets/autorun. muscle memory.
exit with non-zero to signal failure
add test for skip_before_filter with condition
Support array as root element in JSON
fixing arity2 test
halting lambda must be instance execed
use public api for testing rather than grabbing instance variables
inspect the filter when displaying error messages
deprecating string based terminators
use inject rather than multiple assignments
make the compile method thread safe
only dup the options once, the Callback object does not mutate them
Also support extensions in PostgreSQL 9.1, because this has been supported since 9.1.
Remove unnecessary code, because this extension is created on demand in hstore_test.rb.
Removed incorrect warning from application.js templates and replaced it with stub command description
Merge pull request #10626 from firedev/master

Removed incorrect warning from application.js templates and replaced it with stub command description
restore ability to return nil from asset_host proc, add test
Rewrite `activerecord/RUNNING_UNIT_TESTS`

`RUNNING_UNIT_TESTS` is written in an unclear and confusing manner. This commit
attempts to correct that.

Thanks to zzak and vipulnsward for feedback.