Update 03_WebDriver.md

fixing markup and other typos and also trimming down the code so that the example looks precise
Update 06_Worst_Practices.md

Add link spidering as a future topic
added WebDriver Intro
Merge pull request #25 from zacc/master

Add link spidering to Worst practice docs
Merge pull request #24 from rivlinp/patch-2

Update 03_WebDriver.md
hub&node notes
updated hub and nodes
Merge pull request #26 from manoj9788/master

WebDriver Intro
Correcting info about PhantomJSDriver
Fixing indentation for a basic code example.
Merge branch 'master' of https://github.com/SeleniumHQ/selenium-docs
Merge pull request #27 from orieken/master

08_Record_and_Playback
Linting; no functional changes
Merge remote-tracking branch 'upstream/master'