feat (directives/icon): add icon directive to match Bootstrap's style
fix (BootstrapUI): fix the problem with directive load priority
feat (buMain): add preloader
feat (bu$loader): allow for specifying directives which provide their own path
fix (bu$loader): allow for specifying directives which provide their own path
feat (buMain): add filter inclusion to run phase
feat (filters/paginator): add paginator filter which enables windowed view over a collection of items
feat (filters/range): add range selector filter
fix (filters/paginator): change paginator to show everything by default
feat (directives/grid): add grid directive in its initial state.

This directive supports many properties and actions expected of a grid, though at the moment compatibility with data from a remote resource has not been tested in terms of page change event

Todo: emit page change event whenever applicable
feat (buMain): add grid to the set of default directives