first working test program

measures :
- compression ratio with / without dictionary
- create one dictionary per block
- memory budget for dictionaries
- decompression speed, using one different dictionary per block

current limitations :
- only one file
- 4K blocks only
- automatic dictionary built with 4K size

dictionary can be selected on command line, with -D

contrib/largeNbDicts/.gitignore

@@ -0,0 +1,2 @@
+# build artifacts
+largeNbDicts