Extend 'pack' feature by adding option to keep repo's hierarchy, and warn about external deps.

`bam_cli.py pack` command now takes two more (optional) parameters, one
to specify the base directory of the repository, and one to enable
warnings when 'external' dependencies (to given base dir) are found.

Note that by default, base directory is the directory of the packed
.blend file (such that default behavior does not change at all).

See CLI help for more.

bam/blend/blendfile_pack.py

@@ -111,7 +111,16 @@ def pack(
         # but in some cases we wan't to use a path higher up.
         # base_dir_src,
         blendfile_src, blendfile_dst,
+
+        # the path to the top directory of the project's repository.
+        # the packed archive will reproduce the exact same hierarchy below that base path
+        # if set to None, it defaults to the given blendfile_src's directory.
+        # especially useful when used together with the warn_remap_externals option.
+        repository_base_path=None,
+
+        # type of archive to produce (either ZIP or plain usual directory).
         mode='ZIP',
+
         # optionally pass in the temp dir
         base_dir_dst_temp=None,
         paths_remap_relbase=None,
@@ -140,6 +149,8 @@ def pack(
         # do _everything_ except to write the paths.
         # useful if we want to calculate deps to remap but postpone applying them.
         readonly=False,
+        # Warn when we found a dependency external to given repository_base_path.
+        warn_remap_externals=False,
         # dict of binary_edits:
         # {file: [(ofs, bytes), ...], ...}
         # ... where the file is the relative 'packed' location.
@@ -201,7 +212,8 @@ def pack(
         import time
         t = time.time()
 
-    base_dir_src = os.path.dirname(blendfile_src)
+    base_dir_src = os.path.dirname(blendfile_src) if repository_base_path is None \
+                                                  else os.path.normpath(os.path.abspath(repository_base_path))
     base_dir_dst = os.path.dirname(blendfile_dst)
     # _dbg(blendfile_src)
     # _dbg(blendfile_dst)
@@ -351,6 +363,9 @@ def pack(
         path_src = blendfile_path_walker.utils.abspath(path_rel, fp.basedir)
         path_src = os.path.normpath(path_src)
 
+        if warn_remap_externals and b".." in os.path.relpath(path_src, base_dir_src):
+            yield report("  %s:   %r\n" % (colorize("non-local", color='bright_yellow'), path_src))
+
         if filename_filter and not filename_filter(path_src):
             yield report("  %s:     %r\n" % (colorize("exclude", color='yellow'), path_src))
             continue