Merge pull request #607 from cloudant/prepare-2.4.1-release

Prepare 2.4.1 release

- [NEW] `Database` methods `read`, `contains`, `create`, and `delete`…

… now accept local

  (non-replicating documents). These documents must have their document ID prefixed with `_local/`
  and must have their revision ID set to `null` (where applicable).
- [FIXED] Fixed purge_seq to return a String object when replicating with CouchDB 2.3 databases.

- [NEW] Added API for specifying a list of document IDs in the filter…

…ed pull replicator.

- [IMPROVED] Forced a TLS1.2 `SSLSocketFactory` where possible on Android API versions < 20 (it is
  already enabled by default on newer API levels).

- [NEW] Added API for specifying a mango selector in the filtered pul…

…l replicator

- [IMPROVED] Improved efficiency of sub-query when picking winning
  revisions. This improves performance when inserting revisions,
  including during pull replication.
- [UPGRADED] Upgraded to version 2.12.0 of the `cloudant-http` library.

- [NEW] Added API for upcoming IBM Cloud Identity and Access

  Management support for Cloudant on IBM Cloud. Note: IAM API key
  support is not yet enabled in the service.
- [IMPROVED] Updated documentation by replacing deprecated links with the latest Bluemix or CouchDB links.
- [IMPROVED] Added `seq_interval` to improve `Changes` API throughput when replicating from
             a CouchDB 2.x endpoint.
- [UPGRADED] Upgraded to version 2.11.0 of the `cloudant-http` library.

- [FIXED] Removed cloudant-sync-datastore-android project dependency

  on com.google.android:android. This dependency was inadvertently
  made a run-time dependency where it should have been a build-time
  dependency.

- [IMPROVED] Increased the resilience of replication to network failu…

…res.

- [FIXED] NPE when accessing indexes created in earlier versions that were
  migrated to version 2.
- [FIXED] Exception fetching attachments on a deleted revision.
- [FIXED] Correctly schedule periodic replications after WiFi connections have
  been lost.

- [BREAKING CHANGE] With the release of version 2.0 of the library,

  there are a large number of breaking changes to package names,
  classes and methods. API users will need to make changes to their
  existing code in order to use this version of the library. Consult
  the [migration guide](https://github.com/cloudant/sync-android/blob/2.0.0/doc/migration.md) for a comprehensive list of
  changes and suggested strategies to migrate your code.
- [BREAKING CHANGE] The `name` field has been removed from
  `Attachment`. Additionally, the `name` argument has been removed
  from the `UnsavedStreamAttachment` constructors. The name of the
  attachment is the key used to add or retrieve the attachment to or
  from the attachments map.
- [IMPROVED] `DocumentStore.getInstance()` will try to create all
  necessary sub-directories in order to construct the path represented
  by the `File` argument. This differs from the behaviour of the 1.x
  versions of the library which would only attempt to create one level
  of directories.
- [REMOVED] The `batchLimitPerRun` property has been removed from the
  Pull and Push replicator builders. There is no limit to the number
  of batches in a replicator run - the replicator will run to
  completion unless an error occurs.
- [IMPROVED] Removed limitation on `DocumentStore` names. Under the
  old `Datastore` API, the directory containing the SQLite database
  had to conform to the CouchDB database name restrictions. This no
  longer applies.
- [NOTE] The "CRUD Guide" markdown document (previously located in
  `doc/crud.md`) has been migrated to a
  [java source file](https://github.com/cloudant/sync-android/blob/2.0.0/doc/CrudSamples.java).
- [NEW] `advanced()` getter on `DocumentStore` for specialist advanced use cases.
  Adds support for creating specific document revisions with history.
- [FIXED] Issue with double encoding of restricted URL characters in credentials when using
  `ReplicatorBuilder`.
- [FIXED] Issue where push replicating a large number of attachments
  could exhaust the operating system file handle limit, on some
  platforms.
- [FIXED] Issue querying indexed fields when combining the `$not` and
  `$size` operators.

- [FIXED] Issue where replicator would not get the latest revision if…

… `_bulk_get`

   was available.

- [FIXED] Issue performing cookie authentication in version 1.1.3.