Renamed FillHistBase files to ModulesBase and the class to
modules::BaseModule.
Renamed once more, so that it's now BaseModule and contiained in the
global namespace
Put back the TDirectory include for now, too much in one go.
Missed changing include when I change from ModuleBase to BaseModule
Big sed search and replace to change name of FillHistBase to BaseModule
Command used was:
```bash
for i in **;do sed -i -e 's!FillHistBase!BaseModule!g' $i;done
```
Merge branch 'feature/BK_rename_FillHistBase' into develop

Renames FillHistBase to BaseModule as discussed on issue #76