[BENCHMARKS]
* NEW: Add a new 'btree' benchmark, that does a lot of object creation and recursive function calls.
* NEW: Rename the 'string' benchmark as 'string1', to avoid name clashes in Python.
* BUG: Fix the HTML table generation.
[BENCHMARK]
* NEW: Add java benchmarks. Note that 'string' and 'string2' benchmarks are too slow when run with the Java interpreter. So they are just run with Java and JIT compilation enabled.