Add new option for detailed logging on dependency resolving

This adds command-line arg and config option, with option enabled
aptly is more verbose on internal depeendency resolving cycles:

```
Missing dependencies: file-rc (>= 0.8.16) [amd64], python:any (>= 2.7.1-0ubuntu2) [amd64], python3:any (>= 3.3.2-2~) [amd64], file-rc [amd64], perl (<< 5.17) [amd64], iptables-router (>= 1.2.3) [amd64], systemd [amd64], sgml-base (>= 1.26+nmu2) [amd64], sed (>= 4.1.2-8) [amd64]
Unsatisfied dependency: file-rc (>= 0.8.16) [amd64]
Unsatisfied dependency: python:any (>= 2.7.1-0ubuntu2) [amd64]
Unsatisfied dependency: python3:any (>= 3.3.2-2~) [amd64]
Unsatisfied dependency: file-rc [amd64]
Unsatisfied dependency: perl (<< 5.17) [amd64]
Unsatisfied dependency: iptables-router (>= 1.2.3) [amd64]
Unsatisfied dependency: systemd [amd64]
Injecting package: sgml-base_1.26+nmu4ubuntu1_all
Injecting package: sed_4.2.2-4ubuntu1_amd64
```

cmd/cmd.go

@@ -113,6 +113,7 @@ package environment to new version.`,
 	cmd.Flag.Bool("dep-follow-source", false, "when processing dependencies, follow from binary to Source packages")
 	cmd.Flag.Bool("dep-follow-recommends", false, "when processing dependencies, follow Recommends")
 	cmd.Flag.Bool("dep-follow-all-variants", false, "when processing dependencies, follow a & b if dependency is 'a|b'")
+	cmd.Flag.Bool("dep-verbose-resolve", false, "when processing dependencies, print detailed logs")
 	cmd.Flag.String("architectures", "", "list of architectures to consider during (comma-separated), default to all available")
 	cmd.Flag.String("config", "", "location of configuration file (default locations are /etc/aptly.conf, ~/.aptly.conf)")
 

cmd/mirror_update.go

@@ -69,7 +69,7 @@ func aptlyMirrorUpdate(cmd *commander.Command, args []string) error {
 		}
 
 		var oldLen, newLen int
-		oldLen, newLen, err = repo.ApplyFilter(context.DependencyOptions(), filterQuery)
+		oldLen, newLen, err = repo.ApplyFilter(context.DependencyOptions(), filterQuery, context.Progress())
 		if err != nil {
 			return fmt.Errorf("unable to update: %s", err)
 		}

cmd/repo_move.go

@@ -115,7 +115,7 @@ func aptlyRepoMoveCopyImport(cmd *commander.Command, args []string) error {
 		}
 	}
 
-	toProcess, err := srcList.Filter(queries, withDeps, dstList, context.DependencyOptions(), architecturesList)
+	toProcess, err := srcList.FilterWithProgress(queries, withDeps, dstList, context.DependencyOptions(), architecturesList, context.Progress())
 	if err != nil {
 		return fmt.Errorf("unable to %s: %s", command, err)
 	}

cmd/snapshot_filter.go

@@ -66,7 +66,7 @@ func aptlySnapshotFilter(cmd *commander.Command, args []string) error {
 	}
 
 	// Filter with dependencies as requested
-	result, err := packageList.Filter(queries, withDeps, nil, context.DependencyOptions(), architecturesList)
+	result, err := packageList.FilterWithProgress(queries, withDeps, nil, context.DependencyOptions(), architecturesList, context.Progress())
 	if err != nil {
 		return fmt.Errorf("unable to filter: %s", err)
 	}

cmd/snapshot_pull.go

@@ -96,7 +96,7 @@ func aptlySnapshotPull(cmd *commander.Command, args []string) error {
 	}
 
 	// Filter with dependencies as requested
-	result, err := sourcePackageList.Filter(queries, !noDeps, packageList, context.DependencyOptions(), architecturesList)
+	result, err := sourcePackageList.FilterWithProgress(queries, !noDeps, packageList, context.DependencyOptions(), architecturesList, context.Progress())
 	if err != nil {
 		return fmt.Errorf("unable to pull: %s", err)
 	}

cmd/snapshot_search.go

@@ -99,8 +99,8 @@ func aptlySnapshotMirrorRepoSearch(cmd *commander.Command, args []string) error
 		}
 	}
 
-	result, err := list.Filter([]deb.PackageQuery{q}, withDeps,
-		nil, context.DependencyOptions(), architecturesList)
+	result, err := list.FilterWithProgress([]deb.PackageQuery{q}, withDeps,
+		nil, context.DependencyOptions(), architecturesList, context.Progress())
 	if err != nil {
 		return fmt.Errorf("unable to search: %s", err)
 	}