Finally fix Tango import paths.
We don't install Tango in our build system, so the user could always choose a different layout, but this matches the default.
Fixed LDC 1 config file installation.
Thanks to SiegeLord for the meat of the patch.
Search for LDC-specific modules first.
This commit flips the order of the import paths so that the directories we install our stuff to are searched first. This avoids problems if DMD's has been installed to the same directory.
Define version Tango in the config file
Added new config files missing from 4703232.
These will be picked for (and renamed on) installation and contain absolute paths for the directories involved.