Add on doc custom paths to stats and report files

This pull request should add that we can be able to
define the absolute paths to generate the statsFileName or
reportFileName.

Relates to webpack-contrib#186 webpack-contrib#185

README.md

@@ -56,11 +56,11 @@ new BundleAnalyzerPlugin(options?: object)
 |**`analyzerMode`**|One of: `server`, `static`, `disabled`|Default: `server`. In `server` mode analyzer will start HTTP server to show bundle report. In `static` mode single HTML file with bundle report will be generated. In `disabled` mode you can use this plugin to just generate Webpack Stats JSON file by setting `generateStatsFile` to `true`. |
 |**`analyzerHost`**|`{String}`|Default: `127.0.0.1`. Host that will be used in `server` mode to start HTTP server.|
 |**`analyzerPort`**|`{Number}`|Default: `8888`. Port that will be used in `server` mode to start HTTP server.|
-|**`reportFilename`**|`{String}`|Default: `report.html`. Path to bundle report file that will be generated in `static` mode. Relative to bundle output directory (which is `output.path` in webpack config).|
+|**`reportFilename`**|`{String}`|Default: `report.html`. Path to bundle report file that will be generated in `static` mode. It can be either an absolute path or a path relative to a bundle output directory (which is output.path in webpack config).|
 |**`defaultSizes`**|One of: `stat`, `parsed`, `gzip`|Default: `parsed`. Module sizes to show in report by default. [Size definitions](#size-definitions) section describes what these values mean.|
 |**`openAnalyzer`**|`{Boolean}`|Default: `true`. Automatically open report in default browser.|
 |**`generateStatsFile`**|`{Boolean}`|Default: `false`. If `true`, webpack stats JSON file will be generated in bundle output directory|
-|**`statsFilename`**|`{String}`|Default: `stats.json`. Name of webpack stats JSON file that will be generated if `generateStatsFile` is `true`. Relative to bundle output directory.|
+|**`statsFilename`**|`{String}`|Default: `stats.json`. Name of webpack stats JSON file that will be generated if `generateStatsFile` is `true`. Relative to bundle output directory. Custom: `path/to/folder/stats.json`. You can generate the `statsFileName` file outside of the bundle output directory defining the absolute file path.|
 |**`statsOptions`**|`null` or `{Object}`|Default: `null`. Options for `stats.toJson()` method. For example you can exclude sources of your modules from stats file with `source: false` option. [See more options here](https://webpack.js.org/configuration/stats/). |
 |**`excludeAssets`**|`{null\|pattern\|pattern[]}` where `pattern` equals to `{String\|RegExp\|function}`|Default: `null`. Patterns that will be used to match against asset names to exclude them from the report. If pattern is a string it will be converted to RegExp via `new RegExp(str)`. If pattern is a function it should have the following signature `(assetName: string) => boolean` and should return `true` to *exclude* matching asset. If multiple patterns are provided asset should match at least one of them to be excluded. |
 |**`logLevel`**|One of: `info`, `warn`, `error`, `silent`|Default: `info`. Used to control how much details the plugin outputs.|