Add a temporary name filter for the main view.

By using 'F' in the main view you can enter a regex
that will be used to filter the view based on the torrent name.
To remove the filter set the input to empty.
This is adding a 'view.temp_filter' property and a 'match{}' function.
For example with Ctrl+X you could do:
command> view.temp_filter=main,"match={d.name=,.*linux.*iso}"

doc/old/rtorrent.1

@@ -99,6 +99,9 @@ Delete the file the torrent is tied to, and clear the association.
 .TP
 \fBI\fR
 Toggle whether torrent ignores ratio settings.
+.TP
+\fBF\fR
+Add a temporary name based regex filter to the current view.
 .SS "DOWNLOAD VIEW KEYS"
 .TP
 \fB->\fR

doc/old/rtorrent.1.xml

@@ -225,6 +225,13 @@ Toggle whether torrent ignores ratio settings.
           </para></listitem>
         </varlistentry>
 
+        <varlistentry>
+          <term>F</term>
+          <listitem><para>
+Add a temporary name based regex filter to the current view.
+          </para></listitem>
+        </varlistentry>
+
       </variablelist>
 
     </refsect2>