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`.