Make httpserver "git submodule" friendly

[Godzil]

I've made a fork of the Lua WebIDE from @moononournation (cf: https://github.com/Godzil/nodemcu-webide )

To make thing easier to evolve and always use the latest version of httpserver (and not use an hardcoded version) I moved things around to use both httpserver and uploader as git submodules. That works great but httpserver makefile was not thought to not be used as the main makefile as set some parameter internally and we have to edit the file by hand.

To get around that, the makefile of my project after getting the data from the httpserver project patch the makefile to be more compatible. I also do other patches, but these one are really specific for my needs and I don't think they would be really usefull and welcome on the normal version.

The main patch is basically some small changes on the makefile:

See: https://github.com/Godzil/nodemcu-webide/blob/master/patchs/httpserver_makefile.patch

For the rest I basically rename init.lua to httpserver-start.lua and add it to the compilation list.

I still have to figure a good way to be able to let the webide user change the configuration without changing too much of httpserver, if you have any idea, it is welcome!

To make thing more clear, I would like to try to do as least changes as possible on httpserver through patches and keep it as clean as possible so updating the submodule would break as little as possible.

[marcoskirsch]

I thought it was a shame that https://github.com/moononournation forked the server. He's really sharp and doing some really great work. I like your approach. If you want to do a PR I'm ok with it. If @moononournation is ok re-merging projects then even better.