Add server reference to bundler

[fusepilot]

I need to get the development server's port number for use in a plugin. Attaching the server to the bundler allows me to call bundler.server.address().port. This seems to be the only way to access it since the server's port can vary if the user provided port is already being used.

[brandon93s]

Actually, .serve() returns the server. Is that not sufficient?

Afterthought.

[codecov-io]

Codecov Report

Merging #822 into master will decrease coverage by 3.25%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #822      +/-   ##
==========================================
- Coverage   93.41%   90.16%   -3.26%     
==========================================
  Files          68       68              
  Lines        3753     3181     -572     
==========================================
- Hits         3506     2868     -638     
- Misses        247      313      +66

Impacted Files	Coverage Δ
src/Bundler.js	92.83% <100%> (+0.02%)	⬆️
src/Asset.js	66.94% <0%> (-31.36%)	⬇️
src/utils/installPackage.js	77.41% <0%> (-19.46%)	⬇️
src/utils/config.js	76.92% <0%> (-17.45%)	⬇️
src/assets/StylusAsset.js	72.5% <0%> (-16.25%)	⬇️
src/Logger.js	81.9% <0%> (-12.39%)	⬇️
src/assets/GlobAsset.js	90% <0%> (-8.75%)	⬇️
src/visitors/matches-pattern.js	92% <0%> (-8%)	⬇️
src/utils/localRequire.js	95.23% <0%> (-4.77%)	⬇️
src/assets/RawAsset.js	90% <0%> (-4.12%)	⬇️
... and 18 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 852f6b3...842e955. Read the comment docs.

[fusepilot]

Wouldn't .serve() spin up a new server instance? I tried it and the build errors with

loadedAssets is not iterable
  at Bundler.bundle (.../parcel-bundler/src/Bundler.js:179:61)

[brandon93s]

for use in a plugin

Missed this part. Expecting the CLI to continue to call serve and having the server be available to your plugin by keeping a reference to it. 👍

[lbguilherme]

Do:

     this.server = await Server.serve(this, port, https);
     this.bundle();
     return this.server;

[fusepilot]

I don't see how this change could cause the AppVeyor build to fail. Do I need to do anything?

[DeMoorJasper]

@fusepilot it's a rust test that fails from time to time, no need to worry about it