Host/LQ order swap + contig failsafe redo

Changed the order that Quackers operates.
-> Performs host filter, then Low-Quality filter.

Changed the contig failsafe option:
-> now it's a choice between MEGAHIT and MetaSpades.
-> Select it in the config. Default: megahit

Contig failsafe

Includes a new contig failsafe:
If for some reason MetaSpades fails, Megahit will run.

initial release

v1.0.0

added modded_scripts