Add Edge target and adapt options page to Edge

Now the extension can be built with Edge as a target. This change also
adapts the option page for Edge so it doesn't have a horizontal
scrollbar.

Fixed: translateselectedtext:6
Change-Id: Ie0a38b85d1c604610942b00269004c51fc02963d
diff --git a/tools/release.bash b/tools/release.bash
index b838100..91f6b20 100644
--- a/tools/release.bash
+++ b/tools/release.bash
@@ -14,9 +14,8 @@
     -h, --help     show this help message and exit
     -c, --channel  indicates the channel of the release. Can be "beta"
                    or "stable". Defaults to "stable".
-    -b, --browser  indicates the target browser for the release. As of
-                   now it can only be "chromium", which is also the
-                   default value.
+    -b, --browser  indicates the target browser for the release. Can be
+                   "chromium" or "edge". Defaults to "chromium".
     -f, --fast     indicates that the release shouldn't generate the
                    i18n credits JSON file.
 
@@ -64,7 +63,7 @@
   exit
 fi
 
-if [[ $browser != "chromium" ]]; then
+if [[ $browser != "chromium" && $browser != "edge" ]]; then
   echo "browser parameter value is incorrect." >&2
   usage
   exit