Added useful feature: include other paths in sami

This way you can include other repositories into
the Salt.Mine XML:

  <salt-mine>
    <salt-grain>
      ...
    </salt-grain>
    <include>http://from.other.source/repository.xml</include>
  </salt-mine>

src/lay/lay/laySaltGrains.cc

@@ -23,6 +23,7 @@
 #include "laySaltGrains.h"
 #include "tlString.h"
 #include "tlFileUtils.h"
+#include "tlLog.h"
 
 #include <QDir>
 #include <QFileInfo>
@@ -235,6 +236,7 @@ SaltGrains::from_path (const std::string &path, const std::string &prefix)
 
 static tl::XMLElementList s_group_struct =
   tl::make_member (&SaltGrains::name, &SaltGrains::set_name, "name") +
+  tl::make_member (&SaltGrains::include, "include") +
   tl::make_element (&SaltGrains::begin_collections, &SaltGrains::end_collections, &SaltGrains::add_collection, "group", &s_group_struct) +
   tl::make_element (&SaltGrains::begin_grains, &SaltGrains::end_grains, &SaltGrains::add_grain, "salt-grain", SaltGrain::xml_elements ());
 
@@ -254,6 +256,23 @@ SaltGrains::load (tl::InputStream &p)
   s_xml_struct.parse (source, *this);
 }
 
+void
+SaltGrains::include (const std::string &src)
+{
+  if (! src.empty ()) {
+
+    if (tl::verbosity () >= 20) {
+      tl::log << "Including package index from " << src;
+    }
+
+    lay::SaltGrains g;
+    g.load (src);
+    m_collections.splice (m_collections.end (), g.m_collections);
+    m_grains.splice (m_grains.end (), g.m_grains);
+
+  }
+}
+
 void
 SaltGrains::save (const std::string &p) const
 {

src/lay/lay/laySaltGrains.h

@@ -108,6 +108,13 @@ public:
    */
   void set_path (const std::string &p);
 
+  /**
+   *  @brief Includes a list from an external source into this list
+   *  This method reads the other list from the source (an URL) and
+   *  merges it into this.
+   */
+  void include (const std::string &src);
+
   /**
    *  @brief Gets the collections which are members of this collection (begin iterator)
    */