Use https links. Use iota for pasteType and pasteState to preserve type

assets/templates/html/index.html.tmpl

@@ -9,7 +9,7 @@ the command line.
 ## USAGE
 
     # Upload a file
-    curl -F'file=@yourfile.png' <a href="{{.Request.Host}}">{{.Request.Host}}</a>
+    curl -F'file=@yourfile.png' <a href="//{{.Request.Host}}">https://{{.Request.Host}}</a>
 
     # Shorten a URL
     curl -F'shorten=http://example.com/some/long/url' <a href="//{{.Request.Host}}">https://{{.Request.Host}}</a>
@@ -17,4 +17,4 @@ the command line.
     # Shorten a URL with a token to delete it later
     curl -F'shorten=http://example.com/some/long/url' -F'deleteToken=' <a href="//{{.Request.Host}}">https://{{.Request.Host}}</a>
 </pre>
-{{end}}
+{{end}}

assets/templates/txt/index.txt.tmpl

@@ -7,7 +7,7 @@ the command line.
 ## USAGE
 
     # Upload a file
-    curl -F'file=@yourfile.png' {{.Request.Host}}
+    curl -F'file=@yourfile.png' https://{{.Request.Host}}
 
     # Shorten a URL
     curl -F'shorten=http://example.com/some/long/url' https://{{.Request.Host}}

paste.go

@@ -24,17 +24,22 @@ type paste struct {
 	TimeCreated time.Time
 }
 
+// Note: we use iota here. That means removals of pasteType* are not allowed,
+// because this changes the value of the constant. Please add the comment
+// "// deprecated" if you want to remove the constant. Additions are only
+// allowed at the bottom of this block, for the same reason.
 const (
-	pasteTypeUndef      pasteType = 0
-	pasteTypePaste                = 1
-	pasteTypeRedirect             = 2
-	pasteTypeFileUpload           = 3
+	pasteTypeUndef pasteType = iota
+	pasteTypePaste
+	pasteTypeRedirect
+	pasteTypeFileUpload
 )
 
+// Note: we use iota here. See the comment above pasteType*
 const (
-	pasteStateUndef   pasteState = 0
-	pasteStatePresent            = 1
-	pasteStateDeleted            = 2
+	pasteStateUndef pasteState = iota
+	pasteStatePresent
+	pasteStateDeleted
 )
 
 func (t pasteType) String() string {