use xsv-style subcommands like "moonfire-nvr run"

This makes it easier to understand which options are valid with each
command.

Additionally, there's more separation of implementations. The most
obvious consequence is that "moonfire-nvr ts ..." no longer uselessly
locks/opens a database.

src/cmds/ts.rs

@@ -0,0 +1,52 @@
+// This file is part of Moonfire NVR, a security camera digital video recorder.
+// Copyright (C) 2016 Scott Lamb <slamb@slamb.org>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// In addition, as a special exception, the copyright holders give
+// permission to link the code of portions of this program with the
+// OpenSSL library under certain conditions as described in each
+// individual source file, and distribute linked combinations including
+// the two.
+//
+// You must obey the GNU General Public License in all respects for all
+// of the code used other than OpenSSL. If you modify file(s) with this
+// exception, you may extend this exception to your version of the
+// file(s), but you are not obligated to do so. If you do not wish to do
+// so, delete this exception statement from your version. If you delete
+// this exception statement from all source files in the program, then
+// also delete it here.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+use error::Error;
+use recording;
+
+const USAGE: &'static str = r#"
+Usage: moonfire-nvr ts <ts>...
+       moonfire-nvr ts --help
+"#;
+
+#[derive(Debug, RustcDecodable)]
+struct Args {
+    arg_ts: Vec<String>,
+}
+
+pub fn run() -> Result<(), Error> {
+    let arg: Args = super::parse_args(&USAGE)?;
+    super::install_logger(false);
+    for timestamp in &arg.arg_ts {
+        let t = recording::Time::parse(timestamp)?;
+        println!("{} == {}", t, t.0);
+    }
+    Ok(())
+}