Implement "text-align"

"text-align" allows setting the alignment of text, with respect to
other lines and allocated space, without requiring a reference to
the ClutterText (which is private for most widgets).
If not specified, all text is left-aligned.

https://bugzilla.gnome.org/show_bug.cgi?id=622447

src/st/st-theme-node.c

@@ -1761,6 +1761,53 @@ st_theme_node_get_text_decoration (StThemeNode *node)
   return 0;
 }
 
+StTextAlign
+st_theme_node_get_text_align(StThemeNode *node)
+{
+  int i;
+
+  ensure_properties(node);
+
+  for (i = node->n_properties - 1; i >= 0; i--)
+    {
+      CRDeclaration *decl = node->properties[i];
+
+      if (strcmp(decl->property->stryng->str, "text-align") == 0)
+        {
+          CRTerm *term = decl->value;
+
+          if (term->type != TERM_IDENT || term->next)
+            continue;
+
+          if (strcmp(term->content.str->stryng->str, "inherit") == 0)
+            {
+              if (node->parent_node)
+                return st_theme_node_get_text_align(node->parent_node);
+              return ST_TEXT_ALIGN_LEFT;
+            }
+          else if (strcmp(term->content.str->stryng->str, "left") == 0)
+            {
+              return ST_TEXT_ALIGN_LEFT;
+            }
+          else if (strcmp(term->content.str->stryng->str, "right") == 0)
+            {
+              return ST_TEXT_ALIGN_RIGHT;
+            }
+          else if (strcmp(term->content.str->stryng->str, "center") == 0)
+            {
+              return ST_TEXT_ALIGN_CENTER;
+            }
+          else if (strcmp(term->content.str->stryng->str, "justify") == 0)
+            {
+              return ST_TEXT_ALIGN_JUSTIFY;
+            }
+        }
+    }
+  if(node->parent_node)
+    return st_theme_node_get_text_align(node->parent_node);
+  return ST_TEXT_ALIGN_LEFT;
+}
+
 static gboolean
 font_family_from_terms (CRTerm *term,
                         char  **family)