update README

README.md

@@ -1,40 +1,40 @@
 # AttributedString
-A class to work with attributed strings in PHP. Attributed strings are strings that can have multiple attributes per character of the string. Each attribute is a bitfield (boolean array) with the length of the string. This simple data structure can be used to implement lots of interesting things like:
+A collection of classes to work with attributed strings in PHP. Attributed strings are strings that can have multiple attributes per character of the string. Each attribute is a bitmap or boolean array with the length of the string. This simple data structure can be used to implement lots of interesting things like:
  * text-decorations, colors, fonts etc in a word processor (e.g. set a range of the string to have the "bold" attribute)
  * semantic text analysis systems (with attributes like "verb" and "noun")
  * core text extraction
 
 ## Examples
 ```php
   use apemsel\AttributedString\AttributedString;
-  
+
   // ...
-  
+
   $as = new AttributedString("The quick brown fox");
-  
+
   $as->setLength(10, 5, "color"); // "brown" has attribute "color"
   $as->is("color", 12); // == true
   $as->toHtml(); // "The quick <span class=\"color\">brown</span> fox"
-  
+
   $as->setPattern("/[aeiou]/", "vowel"); // vowels have attribute "vowel"
   $as->getAttributes(12); // char at offset 12 has attributes ["color", "vowel"]
-  
+
   $as->combineAttributes("and", "color", "vowel", "colored-vowel"); // also use "or", "not", "xor" to combine attributes
   $as->is("colored-vowel", 12); // "o" of "brown" is a color vowel ;-)
 
   $as->setSubstring("fox", "noun"); // all instances of "fox" have attribute "noun"
   $as->is("noun", 16); // true, char at offset 16 is part of a noun
-  
+
   $as->searchAttribute("vowel"); // 2, first vowel starts at offset 2
   $as->searchAttribute("vowel", 0, true); // [2, 1], first vowel starting at offset 0 is at offset 2 with length 1
-  
+
   // MutableAttributedString can be modified after creation and tries to be smart about the attributes
   $mas = new MutableAttributedString("The brown fox");
   $mas->setLength(0, 13, "bold");
   $mas->insert(4, "quick "); // "The quick brown fox";
   $mas->is("bold", 6) // true, "quick" is now also bold since the inserted text was inside the "bold" attribute
   $mas->delete(10, 6) // "The quick fox"
-  
+
   // TokenizedAttributedString tokenizes the given string, can set attributes by token
   // and maintains the tokens' offsets in the original string.
   $tas = new TokenizedAttributedString("The quick brown fox"); // tokenize using the default whitespace tokenizer