wannesm/dtaidistance v2.0.0

New in v2:

• Numpy is now an optional dependency, also to compile the C library (only Cython is required).
• Small optimizations throughout the C code to improve speed.
• The consistent use of size_t instead of int allows for larger data structures on 64 bit machines and be more compatible with Numpy.
• The parallelization is now implemented directly in C (included if OpenMP is installed).
• The max_dist argument turned out to be similar to Silva and Batista's work on PrunedDTW [7]. The toolbox now implements a version that is equal to PrunedDTW since it prunes more partial distances. Additionally, a use_pruning argument is added to automatically set max_dist to the Euclidean distance, as suggested by Silva and Batista, to speed up the computation (a new method ub_euclidean is available).
• Support in the C library for multi-dimensional sequences in the dtaidistance.dtw_ndim package.