adjoin 0.1.0

• Initial CRAN release.
• Functions for constructing spatial and feature-weighted adjacency matrices.
• K-nearest neighbor graph construction with heat, binary, and cosine kernels.
• Class-based graph tools: class_graph, homogeneous_neighbors, heterogeneous_neighbors.
• Spatial constraint matrices for multi-block data (spatial_constraints, feature_weighted_spatial_constraints).
• Diffusion kernels and commute-time distances on graphs.
• Label similarity matrices (binary_label_matrix, diagonal_label_matrix).