Rename pad option to alignDelimiters

The previous name was very confusing.

Related to remarkjs/remark-lint#217.

index.js

@@ -166,7 +166,7 @@ function markdownTable(table, options) {
 
     index = -1
 
-    if (settings.pad !== false) {
+    if (settings.alignDelimiters !== false) {
       while (++index < cellCount) {
         value = cells[index]
 
@@ -204,7 +204,7 @@ function markdownTable(table, options) {
 
     while (++index < cellCount) {
       // When `pad` is false, make the rule the same size as the first row.
-      if (settings.pad === false) {
+      if (settings.alignDelimiters === false) {
         value = table[0][index]
         spacing = calculateStringLength(stringify(value))
         spacing = spacing > minCellSize ? spacing : minCellSize

readme.md

@@ -134,11 +134,24 @@ function stringLength(cell) {
 }
 ```
 
-###### `options.pad`
+###### `options.alignDelimiters`
 
-Whether to pad the markdown for table cells to make them the same width
-(`boolean`, default: `true`).
-Setting this to `false` will cause the table rows to remain staggered.
+Whether to align the delimiters (`boolean`, default: `true`).
+By default, they are aligned:
+
+```markdown
+| Alpha | B     |
+| ----- | ----- |
+| C     | Delta |
+```
+
+Pass `false` to make them staggered:
+
+```markdown
+| Alpha | B |
+| - | - |
+| C | Delta |
+```
 
 ## Inspiration
 

test.js

@@ -214,7 +214,7 @@ test('table()', function(t) {
         ['master', '0123456789abcdef'],
         ['staging', 'fedcba9876543210']
       ],
-      {pad: false}
+      {alignDelimiters: false}
     ),
     [
       '| Branch | Commit |',
@@ -233,7 +233,7 @@ test('table()', function(t) {
         ['staging', 'fedcba9876543210'],
         ['develop']
       ],
-      {pad: false}
+      {alignDelimiters: false}
     ),
     [
       '| A |  |',