Pylandstats

- flat array approach to the computation of the adjacency matrix with pythran to improve performance (plus fixes a bug on the computation of `total_edge`)
- initialization of `scipy.spatial.cKDTree` with keyword arguments `balanced_tree` and `compact_nodes` set to `False`

- methods plotting multiple axes return only the figure instead of a tuple with the figure and the axes
- settings module that allow configuring metrics' labels in plots, defaulting to FRAGSTATS abbreviations
- chaged CRS in tests to work with pyproj >= 2.0.0
- corrected `figlength` for `figwidth`
- warn when computing metrics that require an unmet minimum number of patches or classes (and their computation returns nan)
- all tests with `unittest.TestCase` assert methods

- added docstrings for `MultiLandscape`, `GradientAnalysis` and `BufferAnalysis`
- raise `ValueError` when using buffer rings around a polygon geometry

- implemented `SpatioTemporalBufferAnalysis` with a dedicated `plot_metric` method
- added buffer ring-wise analysis through a `buffer_rings` boolean argument in `BufferAnalysis`

- float equality comparations with numpy `isclose` method

- implemented `GradientAnalysis` and `BufferAnalysis`
- added optional `geopandas` dependences
- created abstract `MultiLandscape` class
- `Landscape` initialization from ndarray or geotiff (dropped `read_geotiff` method)
- implemented `contagion`
- convolution-based adjacency dataframe
- fixed bug with `class_cond` in `Landscape.compute_arr_edge`