Don't blindly call blame_file! on exceptions in ActiveSupport::Dependencies::Loadable

It is possible under some environments to receive an Exception that is
not extended with Blamable (e.g. JRuby).
ActiveSupport::Dependencies::Loadable#load_dependency blindly call
blame_file! on the exception which throws it's own NoMethodError
exception and hides the original Exception.

This commit fixes #9521
Use sprockets-rails 2.0.0
Use sass-rails 4.0.0.rc2
Keep sub-second resolution when wrapping a DateTime value

Add `DateTime#usec` and `DateTime#nsec` so that `ActiveSupport::TimeWithZone`
keeps sub-second resolution when wrapping a `DateTime` value.

Fixes #10855
Revert "Keep sub-second resolution when wrapping a DateTime value"

This reverts commit a08d3c9bc1f8f60a27f8cc1abe774c644f20b1a9.
Merge pull request #10841 from latortuga/fix-underscore-dependency-tracking

Fix mismatching variable names when using an underscore
Describe ActiveSupport core extensions for BigDecimal, JSON support, and instance variable names.
copy editing AS guide [ci skip]
Use DatabaseTasks.env instead of Rails.env in databases.rake
Properly namespace DatabaseTasks
Merge pull request #10950 from appscape-forks/fix-wrong-method-name

Fix wrong method name
Merge pull request #10924 from pjg/patch-1

Grammar fix [ci skip]
Merge pull request #10925 from senny/10917_test_to_prevent_regression

regression test + mysql2 adapter raises correct error if conn is closed.
Conflicts:

	activerecord/CHANGELOG.md
:scissors:

[ci skip]
Wrap text on 80 columns

This make easier to review the source file

[ci skip]
Merge pull request #10727 from pacoguzman/fix-xml-mini-tests

Fix XmlMini different backends tests
Merge pull request #10960 from pacoguzman/fix-build-due-to-10727

Fix build after #10727
Merge pull request #10969 from davidcelis/case-insensitive-asset-path

Use a case insensitive URI Regexp for #asset_path
fix serialization type cast when value is already unserialized
add test for 9041454def79d8e61cabe49e7c5cb72cef29138b