Added --namespace option to set the namespace of repacked tables

Bumped version number to enforce extension re-creation as the SQL has
been modified.

Current limitations:

- Check for namespace existence: on error temp objects are left around
- What happens to the indexes?
- Tests needed.
- Should the default be the GUC default_tablespace instead of pg_default?
  This is actually an original pg_repack shortcoming, not a regression.

META.json

@@ -2,7 +2,7 @@
    "name": "pg_repack",
    "abstract": "PostgreSQL module for data reorganization",
    "description": "Reorganize tables in PostgreSQL databases with minimal locks",
-   "version": "1.2dev0",
+   "version": "1.2dev1",
    "maintainer": [
        "Josh Kupershmidt <schmiddy@gmail.com>",
        "Daniele Varrazzo <daniele.varrazzo@gmail.com>"
@@ -13,7 +13,7 @@
    "provides": {
       "pg_repack": {
          "file": "lib/pg_repack.sql",
-         "version": "1.2dev0",
+         "version": "1.2dev1",
          "abstract": "Reorganize tables in PostgreSQL databases with minimal locks"
       }
    },