Merge pull request #3284 from lordofhyphens/gh2

Update ISSUE_TEMPLATE.md to hopefully make issues less free-form.

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,22 @@
+### Version
+_Version of Slic3r used goes here_
+
+_Use `About->About Slic3r` for release versions_
+
+_For -dev versions, use `git describe --tag` or get the hash value for the version you downloaded or `git rev-parse HEAD`_
+
+### Operating system type + version
+_What OS are you using, and state any version #s_
+
+### Behavior
+* _Describe the problem_
+* _Steps needed to reproduce the problem_
+  * _If this is a command-line slicing issue, include the options used_
+* _Expected Results_
+* _Actual Results_
+  * _Screenshots from __*Slic3r*__ preview are preferred_
+
+_Is this a new feature request?_
+
+#### STL/Config (.ZIP) where problem occurs
+_Upload a zipped copy of an STL and your config (`File -> Export Config`)_