Modify `index.html` in build directory

[wb14123]

The current implement generate imports of css and js by modify index.html directly, which means change the source code. Why not just generate a modified index.html in build directory, so that the change of dependencies will not change index.html in the source tree.

[Swiip]

I was about to respond that it's not possible because we use the changes not only for the build but also in the development cycle.

But for a lot of other resources, we use the .tmp directory for this exact use and BrowserSync already serve both src and .tmp files.

This is interesting as we could keep the index.html untouch in the src folder, inject resources in the .tmp/index.html and finally have a third one in dist/index.html...

[wb14123]

So will this be implement in the future?

[Swiip]

I'll make some tests about it soon. I think it's a good idea but a keep my final answer for after the tests to check is there is no complications.

[Swiip]

This go up on top of my preoccupation simply because I'd got the case of an injection failure which has emptied my index.html and I had no backup.

But as I started looking at it, I see that it's not easy. Currently each injector:* task takes the file, add some lines and write it at the same place. But there is no task which is able to take the original file and make all injections in the same stream.

Perhaps, this is the solution but it's not a minor change...

[wb14123]

Is it possible to copy the files to other places and run the gulp tasks on that files?

[Swiip]

I started this feature. It implies several important changes but I think it's cleaner this way.

Wait a little more before I can publish the PR.

[Swiip]

The new organization fix this, check out the master or wait for the 0.9.x!

[wb14123]

Great!