Modules are found by autodoc only if written in lower case in the .rst, even if they are upper case in the code

[sradanov]

Module names that are written in upper case in the fortran code are stored in lower case in self.modules of the F90toRst class. This means that the module name has to be given in lower case to .. f:automodule:: in order to get found by the format_module method. Passing the module name as it occurs in the fortran code to . f:automodule:: makes the format_module method raise an F90toRstException('Unknown module'), which is quite counter intuitive.