engineui UI Toolkit initialized (a Bootstrap override)

engineui is a Bootstrap override designed to be later refactored out of Billing into its own project.  To facilitate this, a clear separation between Billing style and engineui style is maintained.  less/engineui contains, for the most part, stub .less files which import their proper Bootstrap parent.  These stubs are ready to accept less code overrides for parent styles.

Note that, for engineui development purposes, all of Bootstrap is compiled to _public/css/engineui.css.  This css file is referenced only by src/engineui.html.  When billing.css is compiled, however, only _referenced_ classes from Bootstrap are carried over.  billing.css is referenced by src/index.html and used by the app.  Case in point: initial billing.css is 12.96 kB, while engineui.css is 132.29 kB.

Also in this pull request is a conversion from single quote to double in some javascript files, and tabs to four spaces (for github happiness).