trying to create an issue template

This should help with people creating issues with no information about
their build or configuration.

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,19 @@
+### Please fill out this form:
+
+### Expected behavior
+
+### Actual behavior
+
+### Steps to reproduce the behavior
+
+### Build details
+
+Operating System (Windows, Mac, Linux, etc.):
+
+Interface (wX, GTK, SDL, MFC, default is wX):
+
+Version of code (pre-built binary version, or commit ref, or just "master"):
+
+Any other relevant build information:
+
+If this is e.g. a joystick or video issue, then the relevant hardware information: