version 0.5.1

Fix bug causing progress bar to jump to 100%
Fix check for data frame in return from R function in exact_extract to allow for derived data frame types such as tibbles.

version 0.5.0

Add exact_resample
Add force_df and full_colnames arguments to exact_extract, to obtain output in a consistent format
Add include_cols and append_cols arguments to exact_extract for linking pixels values or summarized results to input features
Add median and quantile summary operations
Add stack_apply argument to exact_extract to apply an R function individually to each layer in a RasterStack / RasterBrick.
Support returning a data frame from an R function applied to each polygon, then combining those data frames with dplyr::bind_rows

Add named summary operations for variance, standard deviation, coefficient of variation
Improve performance, most dramatically for named summary operations on RasterStack or RasterBrick inputs.
Avoid floating point robustness error when computing stats on certain polygons using different resolution value and weighting rasters.

Add include_cell argument to exact_extract (Michael Sumner)
Fix error thrown by exact_extract when a polygon is partially outside the extent of the value raster but fully within the extent of the weighting raster.
Avoid error when processing polygons with a Z dimension on GEOS 3.6
Support sfc_GEOMETRY inputs if all features are polygonal

Fix incorrect results for some polygons that exactly follow boundaries of raster grid cells
Update tests for compatibility with sf >= 0.9.0

Add weighted mean and weighted sum operations to summarize one raster using the values of another (e.g., population-weighted mean temperature)
Support use of named summary options on RasterStack and RasterBrick inputs (reduces verbosity, improves performance)
Fix memory leak in CPP_coverage_fraction

Attempt to revert to static linking against GEOS if dynamic linking fails
Avoid undefined behavior when calling exact_extract on polygon that does not intersect raster.