Redo checkboxes and radios

- Move disabled radio and checkbox styles to Reboot
- Collapse .radio and .checkbox into single class, .form-check
- Collapse .radio-inline and .checkbox-inline into single class, .form-check-inline
- Require classes for sub-elements in both new classes

dist/css/bootstrap.css

@@ -477,6 +477,11 @@ textarea {
   border-radius: 0;
 }
 
+input[type="radio"]:disabled,
+input[type="checkbox"]:disabled {
+  cursor: not-allowed;
+}
+
 input[type="date"],
 input[type="time"],
 input[type="datetime-local"],
@@ -2242,41 +2247,37 @@ select.form-control:focus::-ms-value {
   margin-bottom: 1rem;
 }
 
-.radio,
-.checkbox {
+.form-check {
   position: relative;
   display: block;
   margin-bottom: 0.75rem;
 }
 
-.radio label,
-.checkbox label {
+.form-check + .form-check {
+  margin-top: -.25rem;
+}
+
+.form-check.disabled .form-check-label {
+  cursor: not-allowed;
+}
+
+.form-check-label {
   padding-left: 1.25rem;
   margin-bottom: 0;
   cursor: pointer;
 }
 
-.radio label input:only-child,
-.checkbox label input:only-child {
-  position: static;
-}
-
-.radio input[type="radio"],
-.radio-inline input[type="radio"],
-.checkbox input[type="checkbox"],
-.checkbox-inline input[type="checkbox"] {
+.form-check-input {
   position: absolute;
   margin-top: .25rem;
   margin-left: -1.25rem;
 }
 
-.radio + .radio,
-.checkbox + .checkbox {
-  margin-top: -.25rem;
+.form-check-input:only-child {
+  position: static;
 }
 
-.radio-inline,
-.checkbox-inline {
+.form-check-inline {
   position: relative;
   display: inline-block;
   padding-left: 1.25rem;
@@ -2285,25 +2286,11 @@ select.form-control:focus::-ms-value {
   cursor: pointer;
 }
 
-.radio-inline + .radio-inline,
-.checkbox-inline + .checkbox-inline {
-  margin-top: 0;
+.form-check-inline + .form-check-inline {
   margin-left: .75rem;
 }
 
-input[type="radio"]:disabled, input[type="radio"].disabled,
-input[type="checkbox"]:disabled,
-input[type="checkbox"].disabled {
-  cursor: not-allowed;
-}
-
-.radio-inline.disabled,
-.checkbox-inline.disabled {
-  cursor: not-allowed;
-}
-
-.radio.disabled label,
-.checkbox.disabled label {
+.form-check-inline.disabled {
   cursor: not-allowed;
 }