Blob improvements.
Blob improvements.

-Abstract base class with .pipe() and .slice() methods.
-fixes to BlobSerivce
-Add rest client for an HTTP based blob service.

foam-framework/foam2,TanayParikh/foam2,jacksonic/vjlofvhjfgm,jacksonic/vjlofvhjfgm,foam-framework/foam2,TanayParikh/foam2,TanayParikh/foam2,foam-framework/foam2,foam-framework/foam2,jacksonic/vjlofvhjfgm,TanayParikh/foam2,foam-framework/foam2