Sqlite::truncate(): Verify `sqlite_sequence` exists before _execute()

`sqlite_sequence` is a dynamic table that's only available when a table in
the database use an auto increment field.  For some cases, eg: databases that
exclusively use uuid for primary keys, this table won't exist and
truncate() call will fail with:

  Error: SQLSTATE[HY000]: General error: 1 no such table: sqlite_sequence
Reduce variable use/duplicate code.
Added/removed newlines to make the code more readable.
flushMethodCache not working if called before cacheMethod

When calling flushMethodCache it correctly empties self::$methodCache but if cacheMethod is called afterwards self::$methodCache gets populated with data from the Cache.
Corrected some grammar in the JsonView class doc blocks
Updated doc block for JsonView's subDir property
Merge pull request #1650 from bcrowe/fix-jsonviewdocs

Corrected some grammar in the JsonView class doc blocks
Update docs for HttpSocket methods.

delete() uses the request body, not the query string.
Updated CakeTime::i18nFormat() doc block description
Merge pull request #1652 from bcrowe/fix-caketimedocs

Updated CakeTime::i18nFormat() doc block description
Fix casing of validation rules in bake
Merge pull request #1656 from dereuromark/master-validation-rules-casing

Fix casing of validation rules in bake
Fixed TreeBehavior::recover() when using scope. Fixes #4062.
Merge pull request #1657 from ADmad/bugfix/tree

Fixed TreeBehavior::recover() when using scope. 

Fixes #4062.
simplify tests
add missing create() for creating a new record.
Merge pull request #1658 from dereuromark/master-tests

correct and simplify tests
Use array_key_exists instead of isset()

This allows contains() to work with null values.

Fixes #4083
Updated doc block readability in bootstrap.php
Merge pull request #1668 from bcrowe/hotfix-bootstrapdocblock

Updated doc block readability in bootstrap.php