Add the button the right way

Fallback to the hack only if button is not supported in pcbnew. Don't 
use the hack on linux because it crashes pcbnew.

Author: qu1ck

InteractiveHtmlBom/__init__.py

@@ -4,10 +4,7 @@
 import wx.aui
 import threading
 import time
-
-plugin = GenerateInteractiveBomPlugin()
-plugin.register()
-
+import sys
 
 def check_for_bom_button():
     # From Miles McCoo's blog
@@ -42,6 +39,12 @@ def callback(_):
             top_tb.Realize()
 
 
-t = threading.Thread(target=check_for_bom_button)
-t.daemon = True
-t.start()
+plugin = GenerateInteractiveBomPlugin()
+plugin.register()
+
+# Add a button the hacky way if plugin button is not supported
+# in pcbnew, unless this is linux.
+if not plugin.pcbnew_icon_support and not sys.platform.startswith('linux'):
+    t = threading.Thread(target=check_for_bom_button)
+    t.daemon = True
+    t.start()

InteractiveHtmlBom/generate_interactive_bom.py

@@ -479,6 +479,9 @@ def defaults(self):
         """
         self.name = "Generate Interactive HTML BOM"
         self.category = "Read PCB"
+        self.pcbnew_icon_support = hasattr(self, "show_toolbar_button")
+        self.show_toolbar_button = True
+        self.icon_file_name = os.path.join(os.path.dirname(__file__), 'icon.png')
         self.description = "Generate interactive HTML page that contains BOM " \
                            "table and pcb drawing."