Corrected ModuleContainer class functions AddModule() and RemoveModule() to return boolean instead of nothing so that it is possible to return errors or success when using these functions in ModuleManager.  Completed implementation of ModuleContainer::GetAvailableSlotInBank() method to search specified slot bank for an available module slot, returning that slot flag or an illegal flag value if no slot is available.
Finally fixed Module Auto-fit, where you drag either a single module, or a stack of modules, onto the center of the fitting window and the server automatically chooses a slot to fit it into, if one is available in that bank, then fits it.  Fixed issues with dragging a stack onto the center of the window where the stack disappeared and nothing appeared in the slots.  Tested draging singles and stacks onto all three slot banks.  Everything seems to work just fine, even when trying to drag stacks or singles into center when entire slot bank is full.  The fit is rejected and modules left in inventory window.
Merge branch 'master' of https://github.com/evemuproject/evemu_server