* Removed build/pluginhost (no more physical rollups, path meta-data) * README -> README.md + HISTORY.md Ran pluginhost unit tests

1). PluginHost broken out into it's own module - 'pluginhost', for use in the Base independant Node 2). PluginHost augmentation removed from base-base, to allow for a ligher, ahem, base Base impl for cases where plugins are not used. base-pluginhost submodule added, which will augment PluginHost to Base. base-pluginhost is part of the 'base' module, so no changes required to existing code which requires 'base' and uses plugins. 3). Updated loader meta-data, so no changes should be required to existing code. Plugin tests pass without change, and DataSource, DD, Overlay plugin examples work.