Use database for handling molecule and avoiding repeat calculations

[Tonylac77]

Use a database to store molecules and results. Each docking and scoring operation can be done on single molecules instead of split SDF files.

Need to be careful of I/O time becoming the bottleneck instead of CPU.
Each molecule can be written as a temp file for input into docking and restoring.

Alternatively, write every molecule/pose to a single SDF file.