add ghostlink for easier edge selection (Fixes #131)

This changes our current svg. We already had a <g id="link-group">
and under it <path class="link graph"> elements (class changes for
selection).

Now we have <g class="link graph"> elements containing two paths:
one for display, one for selection.
the display has stroke-width of 2 (defined in res/css/style.css) and the
selection has stroke-width of 5 and stroke not defined to make it
invisible plus a higher z-index to catch the click.

1 files changed, 6 insertions, 0 deletions

diff --git a/res/css/style.css b/res/css/style.css
index 995eb2ea..2fac294e 100644
--- a/res/css/style.css
+++ b/res/css/style.css
@@ -133,6 +133,12 @@ input:focus {
   z-index:1;
 }
 
+.ghostlink {
+  fill: none;
+  stroke-width: 2px;
+  z-index:2; // higher than link, lower than node
+}
+
 .highlightlink {
   fill: none;
   stroke: #EDE275;