remove charset

Author: noogen

readme.md

@@ -54,8 +54,9 @@ m.diff('tests/file1.txt', 'tests/file2.txt');
 
 **TextFileDiff** constructor also accept optional options object.  Valid options are:
 1. `skipHeader` - boolean indicating if first line should be skipped
-2. `charset` - default to `utf8`
-3. `compareFn` - line comparer function that take in two line (line1 and line2), and `return line1 > line2 ? 1 : (line1 < line2 ? -1 : 0)` allowing you to define how you want to perform line compare.
+2. `compareFn` - line comparer function that take in two line (line1 and line2), and `return line1 > line2 ? 1 : (line1 < line2 ? -1 : 0)` allowing you to define how you want to perform line compare.
+
+> NOTE: use diffStream if you need control over encoding
 
 ## Example
 ```bash