Add v.build.polylines algorithm

python/plugins/processing/algs/grass7/description/v.build.polylines.txt

@@ -0,0 +1,6 @@
+v.build.polylines
+Builds polylines from lines or boundaries.
+Vector (v.*)
+ParameterVector|input|Name of input vector map|-1|False
+ParameterSelection|cats|Category number mode|no;first;multi|0
+OutputVector|output|Polylines

python/plugins/processing/algs/grass7/ext/v_build_polylines.py

@@ -0,0 +1,40 @@
+# -*- coding: utf-8 -*-
+
+"""
+***************************************************************************
+    v_build_polylines.py
+    --------------------
+    Date                 : March 2016
+    Copyright            : (C) 2016 by Médéric Ribreux
+    Email                : medspx at medspx dot fr
+***************************************************************************
+*                                                                         *
+*   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 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************
+"""
+
+__author__ = 'Médéric Ribreux'
+__date__ = 'March 2016'
+__copyright__ = '(C) 2016, Médéric Ribreux'
+
+# This will get replaced with a git SHA1 when you do a git archive
+
+__revision__ = '$Format:%H$'
+
+
+import os
+
+
+def processOutputs(alg):
+    out = alg.getOutputValue('output')
+    command = u"v.out.ogr -c -s -e input={} output=\"{}\" format=ESRI_Shapefile output_layer={}".format(
+        alg.exportedLayers[out],
+        os.path.dirname(out),
+        os.path.splitext(os.path.basename(out))[0]
+    )
+    alg.commands.append(command)
+    alg.outputCommands.append(command)