Update issue templates to modern version

More details here https://blog.github.com/2018-05-02-issue-template-improvements/

.github/bug_report.md

@@ -0,0 +1,7 @@
+---
+name: Bug report
+about: Create a bug report to help us improve
+
+---
+
+Please describe details of your issue as much as possible.

.github/feature_request.md

@@ -0,0 +1,13 @@
+---
+name: Feature request
+about: Suggest an idea for this project
+
+---
+
+Fixes # .
+
+Changes proposed in this pull request:
+ - 
+ - 
+ - 
+