Convert eq damage to float

Converts object damage and maxdamage to a float.  After weapon damage worked again, the level of damage as expressed to integers would be too much damage to weapons given how weapons have been built.

I updated nanite reconstruction in mobact.c to allow for repairing as float, and updated the repairer spec in repairer.c to allow repairing less than 1 maxdam (since many items are 100 maxdam).