Internal: remove IndexCloseListener & Store.OnCloseListener

Closes #9009
Test: added some logging to NodeEnvironmentTests.testDeleteSafe
Plugins: NPE when plugins dir is inaccessible

Steps to reproduce:

1. Download fresh es.
2. `sudo mkdir plugins && sudo chmod 0700 plugins`
3. Start elasticsearch

```
elasticsearch-1.4.1 λ ./bin/elasticsearch
[2014-12-09 12:18:59,025][INFO ][node                     ] [Piotr Rasputin] version[1.4.1], pid[16338], build[89d3241/2014-11-26T15:49:29Z]
[2014-12-09 12:18:59,025][INFO ][node                     ] [Piotr Rasputin] initializing ...
{1.4.1}: Initialization Failed ...
- NullPointerException[null]
```

Closes #8837.
Shutdown: Add support for Ctrl-Close event on Windows platforms to gracefully shutdown node

This commit adds the support for the Ctrl-Close event on Windows using native system calls. This way, it is possible to catch the Ctrl-Close event sent by a 'taskill /pid' command (or when the user closes the console window where elasticsearch.bat was started) and gracefully close the node. Before this commit, the node was simply killed on taskkill/window closing.
Mappings: Reencode transformed result with same xcontent

When I originally wrote the transform feature I didn't think that the
XContentType of the reencoded source mattered.  It actually matters because
payloads for the completion suggester are stored and returned exactly
as encoded by this XContentType.

This revision changes the transform feature from always reencoding with smile
to always reencoding with the provided XContentType to support the completion
suggester.

Closes #8959
Mappings: Include currentFieldName into ObjectMapper errors

Without currentFieldName error is very generic and non informative

Close #9020
Aggregations: Adds methods to get to/from as Strings for Range Aggs

Adds getToAsString and getFromAsString to Range interface and implements them for all range aggregations

Closes #9003
Add index.data_path setting

This allows specifying the path an index will be at.

`index.data_path` is specified in the settings when creating an index,
and can not be dynamically changed.

An example request would look like:

POST /myindex
{
  "settings": {
    "number_of_shards": 2,
    "data_path": "/tmp/myindex"
  }
}

And would put data in /tmp/myindex/0/index/0 and /tmp/myindex/0/index/1

Since this can be used to write data to arbitrary locations on disk, it
requires enabling the `node.enable_custom_paths` setting in
elasticsearch.yml on all nodes.
Seriously, the 140 character limit is there for a reason