Enable local hexo installations by using npx

[xax]

In line run-command.ts:31 you resort to a hard coded hexo command:

const cmd = 'hexo ' + args.join(' ');

Maybe you consider to make it possible to use a project-local hexo installation that uses npx to run hexo from node_modules/.bin/. This would require a configuration option (let's call it npx) to prefix the cmd somewhat like that:

const cmd = ((cfg.npx)? 'npx': '') + 'hexo ' + args.join(' ');