(*) Added Merging mechanism:
    - CMergeManager is the driver
    - CMergeAlgoBase is the base for any merging algorithm (will be run by CMergeManager)
    - CBookKeeper is for book-keeping of clusters after merging
(*) Added an empty ShowerReco2DAlgo which drives Merging + matching + shower/track separation

Kazu
Merge branch 'trunk' of github.com:/larlight/LArLight into trunk
(*) Adding Polygon to dictionary
(*) Modifying example.py and example_allhits.py to use cluster_params::PolyObject instead of cluster_params::container_polygon which is removed now.

Kazu
Merge branch 'trunk' of github.com:/larlight/LArLight into trunk