New benchmark mode in order to have statistics on the size of the envelopes
When computing stats of the envelope sizes, average the results for rows and columns.
Add the possibility to do some logarithmic steps when computing envelopes stats.
Add the maximum size to the envelope sizes stats.
We don't need the entire submatrix query data structure do make some statistics about the envelopes, so just create the trees without the entire DS.
Complete test functions
Change the benchmarking protocol for position queries to prevent compiler and processor optimization (i.e. when making the same function call for different implementations, avoid "caching" behavior).
Change the benchmark protocol for submatrix queries (same reason as previous commit).
Add a bench mode for a single matrix.
Add a mode to benchmark ALL the queries in the same run
Add command line options to enable or disable some flags.