Rio-cogeo

* add more logging and `--quiet` option (46)
* add `--overview-blocksize` to set overview's internal tile size (60)

**Bug fixes:**

* copy tags and description from input to output (19)
* copy input mask band to output mask

**Breaking Changes:**

* rio cogeo now has subcommands: 'create' and 'validate' (6).
* internal mask creation is now optional (--add-mask).
* internal nodata or alpha channel can be forwarded to the output dataset.
* removed default overview blocksize to be equal to the raw data blocksize (60)

* Initial release. Requires Rasterio >= 1.0b1.

* allow non integer nodata value (51)
* fix GDAL blocksize options casting for overview calculation (50)

* Renamed "ycbcr" profile's name to "jpeg" to reflect the compression name.
"ycbcr" profile will raise a "DeprecationWarning" (44)
* "webp" profile has been added to COG profiles. Exploitation of this new
compression mode will require GDAL 2.4 (27)
* Rio-cogeo can calculate the overview level based on the internal tile size
and the dataset width/height (37)

* write tags in output file (31)
* add bilinear, cubic spline, lanczos resampling modes for overviews

* add resampling option for overviews (28)