Move ModuleAdmin support from Compat to Modules where it belongs
Change to use getInstance() for initializations.

Use 2.6 XoopsModuleAdmin directly if possible.

XMF supplied enhancements are implmented as static methods, so 2.6
can use them as well, just use getInstance() to get instantiate the module
admin object, and all is well.

Add the following:
Xmf_Module_Admin::checkModuleVersion($moddir,$minversion)
Xmf_Module_Admin::addConfigAccept($value)
Xmf_Module_Admin::addConfigError($value)
Add constants for Xmf_Module_Admin::checkModuleVersion()
Changing getObject() to getModule() to be like 2.6 implementation