Move src files out of assets dir

* client/assets/src moved to client/src
* build.js moved to client/build.js
* Auto-generated index.html now written to assets/index.html
* Fixed bug where conf.public_http was set in config file ut conf.public_html was being read in httphandler.js
Moving index.html out of the assets folder - the page is not an asset of itself
.gitignore update
Restoring conf.public_http config option for backwards compatibility