Update README with new features

Author: Starli0n

README.md

@@ -5,11 +5,11 @@ Shows diffs between the current file, or selection(s) in the current file, and c
 
 ## Preview
 
-![Preview] (https://github.com/ildarkhasanshin/SublimeFileDiffs/raw/master/preview_1.png)
+![Preview](https://github.com/ildarkhasanshin/SublimeFileDiffs/raw/master/preview_1.png)
 
-![Preview] (https://github.com/ildarkhasanshin/SublimeFileDiffs/raw/master/preview_2.png)
+![Preview](https://github.com/ildarkhasanshin/SublimeFileDiffs/raw/master/preview_2.png)
 
-![Preview] (https://github.com/ildarkhasanshin/SublimeFileDiffs/raw/master/preview_3.png)
+![Preview](https://github.com/ildarkhasanshin/SublimeFileDiffs/raw/master/preview_3.png)
 
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@@ -57,6 +57,11 @@ Add External Diff Tool *(optional)*
 
    This command *may* need to be a full path (e.g. `/usr/local/bin/ksdiff`), if the command isn't in your `PATH`.
 
+It supports:
+
+-   A generic setting `FileDiffs.sublime-settings` which could be overloaded for each parameter in a platform specific configuration `FileDiffs ($platform).sublime-settings` in the `Settings - User`
+-   Environment variable expansions for `cmd` parameter in the settings
+
 
 Commands
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