Merge pull request #25 from dr0i/zvdd

Add zvdd transformations, which can be executed by metatext
Add Xtext project nature to lodmill-rd (for Metatext & DOT editors)
Add simple DOT pipe encoder, refactor N-Triple encoder for reuse
Update Metatext dependencies for DOT pipe support and vis. w/ Zest
Update sample and documentation with stream-tee and DOT encoder
Merge pull request #26 from fsteeg/dot

DOT pipe encoder and visualization with Zest