Sparse memory implementations

Changelog

Implemented enhancements:

• GPU kNNs #21
• Implement temporal addressing for SDNCs #18
• Feature: Sparse Access Memory #4
• SAMs #22 (ixaxaar)
• Temporal links for SDNC #19 (ixaxaar)
• SDNC #16 (ixaxaar)

Merged pull requests:

• Add more tasks #23 (ixaxaar)
• Scale interface vectors, dynamic memory pass #17 (ixaxaar)
• Update README.md #14 (MaxwellRebo)