With this change, the user provides a filter function instead of
an array of layers. Selection layers are created lazily, and
addition/removal of layers is not handled by the control to give
the user more options, as suggested by @elemoine.
This way all styles can be defined on the source layer, by
defining a rule with a select renderIntent. It also will make
addition and removal of layers easier while the select control
is active.
The zoom slider control's initSlider_ function requires that the control's element is inserted in the document. So if initSlider_ is called before the map have a target then the slider isn't correctly initialized. This commit fixes that by defering the slider initialization until the first handleMapPostrender call.
With this commit test files provide namespaces (using goog.provide). This fixes the issue reported by @bartvde where goog objects cannot be used in Jasmine "describe" functions. It also frees us from having to add script tags for the test files in test/ol.html.
