Replace cp with shutils functions for import

This allows the import to work on systems without GNU coreutils
installed (e.g. macOS, where only BSD cp is available by default).
For BSD specifically, the `-T` flag is missing in `cp`.

dotdrop/dotdrop.py

@@ -8,6 +8,8 @@ entry point
 import os
 import sys
 
+import shutil
+
 # local imports
 from dotdrop.options import Options
 from dotdrop.logger import Logger
@@ -421,7 +423,15 @@ def cmd_importer(o):
                     LOG.err('importing \"{}\" failed!'.format(path))
                     ret = False
                     continue
-            cmd = ['cp', '-R', '-L', '-T', dst, srcf]
+            if o.dry:
+                LOG.dry('would copy {} to {}'.format(dst, srcf))
+            else:
+              if os.path.isdir(dst):
+                if os.path.exists(srcf):
+                  shutil.rmtree(srcf)
+                shutil.copytree(dst, srcf)
+              else:
+                shutil.copy2(dst, srcf)
             if o.dry:
                 LOG.dry('would run: {}'.format(' '.join(cmd)))
             else: