README: fixed headings level

Modified all h1 headings except the first one to h2, all h2 under h1 to h3,
etc.
Emit 'listening' and 'error' events

Modified DebugServer to emit 'listening' and 'error' events, added address()
function for getting the server's address. Moved console logs from DebugServer
to bin/inspector.js.

Modified CLI runner (bin/inspector.js) to forward DebugServer events to
the parent process via `process.send`.

Started embedding guide in `docs/embedding.md`.
ChangeLog: updated for version v0.4.0
started work on v0.4.1
tools: implemented update-front-end.sh

Implemented a command-line tool for automatic update of front-end
to the given Blink branch.
front-end: upgraded to Blink branch 1625, r157454
front-end: patched inspector.html

Re-applied node-inspector specific changes after the file was upgraded to the
newer Blink version.
lib,Overrides: support the updated front-end

- Registered additional no-op commands
- Added `column` property to console log messages
- Disabled warning about changes not persisted to filesystem
- Added `hitBreakpoints` to `Debugger.paused` message
- Simplified Debugger._handleChangeLiveOrRestartFrameResponse by removing
  stepIntoAndSendResponse(), as this is handled by front-end now
- Removed patch for `loadXHR()` and implememented source-maps loading using
  the new command `Network.loadResourceForFrontend`.
package.json: changed the next version to 0.5.0
package.json: upgraded to express 3.4
NetworkAgent: support data scheme URLs

Implemented support for data scheme URLs. This allows sourcemap files to be
embedded in the sourceMappingURL in the generated js file.
Fixed wrong hint in error message if web port is used.
Updated AUTHORS.