Tests for isNearDuplicate method
Interface for Near-Duplicate detection libs

and dependency for xxhashing, which will be used to hash features.
Move files
Merge branch 'near-duplicate-detection' of https://github.com/erwinvaneyk/crawljax into near-duplicate-detection
Fix package structure for duplicate detection
Changes in StateVertexImpl to implement near-duplicates
Added tests for generateHash
Implementation of simha.. eh crawlhash
Implementation fixes to pass the tests
Added tests
Added support for multiple feature-types
Make tests for the feature shingles
Add possibility to use different shingle sizes

The possible shingle sizes are now (n is some specified amount):
- n chars
- n words
- n sentences
Made stripper for the head
Made stripper for the redundant whitespace
Use the new domstrippers
Tests for the hamming distance
Check for near duplicates on all vertices in the graph
Refactor tests for CrawlHash
Fix int long problem of the hashes