Updating Readme to include contribution guidelines

Added information for people wishing to contribute to this project.
Merge release branch v0.2 into master

Master is now the main development branch for msnodesql.
Fix for issue #62 - Debugging query callback with node-inspector!

Per the comments from clintwood, the original line:
callback->Call(Undefined().As<Object>(), argc, args);
causes node-inspector to crash if breakpoints are added in any query
callback function.  This change corrects that.
Fixed CLA link in CONTRIBUTING.md
Merge pull request #84 from DMGambone/Error-with-node-inspector-fix

Fix for issue #62 - Debugging query callback with node-inspector!
Update CONTRIBUTORS to include Dino M. Gambone
npm install - no compilation required

Currently when using npm, sqlserver.node must be created by compiling the
extension with node-gyp.

This commit adds an installation script that downloads the appropriate
sqlserver.node file from Microsoft at installation time.

Supports node.js 0.6.x and 0.8.x versions on ia32 and x64 Windows.