update readme

Author: breeve1

README.md

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 An easy to use SQL based web scraper language. If you know SQL and a little about CSS selectors and want to capture data from the web, this is the tool for you.
 ## Downloads
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-Found [here](https://github.com/bitsummation/pickaxe/releases).
+Found [here](https://github.com/bitsummation/pickaxe/releases). It requires .NET framework 4.0
 ## Quickstart
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 Pickaxe uses SQL statements combined with CSS selectors to pick out text from a web page. Download the tool from above and unzip the contents and double click on **Pickaxe.Studio.exe**. Below are some simple examples.