Revert "Fixed some grammatical errors in raw_email_with_invalid_characters_in_content_type. Picky, I know."

This reverts commit 30aa4e6c.

Reason: docrails doesn't allow changing code. As much as this is a plain
text file, I would still like to enforce the policy strictly.

Add db/*.sqlite3-journal to .gitignore

These can pop up while the SQLite DB is being written to.

remove warnings about @variable_for_layout

don't encode an UTF-8 encoded template

This reverts commit ce0cf7d6.

cp is not a valid command in DOS systems.
This reverts commit 7d11c129.

  from Ruby stdlib.

Fix database tasks in test namespace.

This is mostly the same as 876bade5
that was reverted due to test failures, but now with a correction.

This reverts commit a0edfb4d, reversing
changes made to 4012fcff.

Fix database tasks in test namespace.

Ruby assumes curly braces in foo {} as a block, for hash we need to put parentheses or omit braces

After 15fb4302 the default location of the :sql schema_format location was
changed from environment_name.sql to structure.sql. This pull request updates
a reference to the old schema format location in the migration guides.