Takes a screenshot of the entire screen and embeds it into the log.

The screenshot is saved into file screen_capture_%d_%d.png under the directory defined in {{selenium.screenshot.folder}} in {{jspringbot.properties}}.

*Example:*
| Capture Screenshot |
| Capture Screenshot | style=grayscale |
| Capture Screenshot | style=x=40,y=10,width=200,height=100 |
| Capture Screenshot | style=grayscale,x=40,y=10,width=200,height=100 |

=>

| captures the page screen shot
| captures the page screen shot and the image will be grayscaled
| captures the page screen shot, this also crops the image given the crop location and dimension.
