Fix #416: Add an issue and PR template.

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,32 @@
+<!--
+### Before Submitting
+
+- You checked the [faq](https://github.com/junegunn/vim-plug/wiki/faq) for common problems.
+- Check your [requirements](https://github.com/junegunn/vim-plug/wiki/requirements) are satisfied.
+- You are not going to suggest vim-plug manage itself like Vundle, see #240, #364, #367 ...
+-->
+
+Explain the problem here ...
+
+------------------------------
+
+<!-- Put the contents of `:version` below -->
+```
+
+```
+
+<!-- Check all that apply. -->
+- Type:
+    - [ ] Bug
+    - [ ] Enhancement
+    - [ ] Feature Request
+    - [ ] Question
+- OS:
+    - [ ] All/Other
+    - [ ] Linux
+    - [ ] OS X
+    - [ ] Windows
+- Vim:
+    - [ ] Terminal Vim
+    - [ ] GVim
+    - [ ] Neovim

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,8 @@
+<!-- ## Before Submitting
+
+- You made sure the existing tests/travis build works.
+- You made sure any new features were tested where appropriate.
+- You checked a similar feature wasn't already turned down by searching issues & PRs.
+-->
+
+Describe the details of your PR ...