docs(grid-list): added docs for basic grid-list (#491)

Author: kara

src/components/grid-list/README.md

@@ -0,0 +1,115 @@
+# md-grid-list
+
+`md-grid-list` is an alternative list view that arranges cells into grid-based layout. 
+See Material Design spec [here](https://www.google.com/design/spec/components/grid-lists.html).
+
+## Usage
+
+### Simple grid list
+
+To use `md-grid-list`, first import the grid list directives and add them to your component's directives 
+array:
+
+```javascript
+@Component({
+  ...
+  directives: [MD_GRID_LIST_DIRECTIVES]
+})
+```
+
+In your template, create an `md-grid-list` element and specify the number of columns you want for
+your grid using the `cols` property (this is the only mandatory attribute). 
+
+You can define each tile using an `md-grid-tile` element, passing any tile content between its tags.
+
+Tiles are greedily placed in the first position of the grid that fits them, so row count depends on 
+how many tiles can fit in each row, given the col count and the colspan/rowspan of each tile.
+
+```html
+<md-grid-list cols="4" [style.background]="'lightblue'">
+   <md-grid-tile>One</md-grid-tile>
+   <md-grid-tile>Two</md-grid-tile>
+   <md-grid-tile>Three</md-grid-tile>
+   <md-grid-tile>Four</md-grid-tile>
+</md-grid-list>
+```
+
+Output:
+
+<img src="https://material.angularjs.org/material2_assets/grid-list/basic-grid-list.png">
+
+## Grid list config
+
+####`cols`
+
+The `cols` property controls the number of columns displayed in your grid. It must be set or the 
+grid list will not be able to generate your layout.
+
+Ex: `<md-grid-list cols="3">...`
+
+Default: There is no reasonable default value for this, so if it is unspecified, the grid list will 
+throw an error.
+
+####`rowHeight`
+
+Row height for the list can be calculated in three ways:
+
+1. **Fixed height**: The height can be in `px`, `em`, or `rem`.  If no units are specified, `px` 
+units are assumed. 
+   
+   Ex: `<md-grid-list cols="3" rowHeight="100px">...`
+        
+2. **Ratio**: This ratio is width:height, and must be passed in with a colon, not a decimal.
+
+   Ex: `<md-grid-list cols="3" rowHeight="4:3">...`.
+        
+3. **Fit**:  This mode automatically divides the available height by the number of rows.  Please note
+the height of the grid-list or its container must be set.  
+
+   Ex: `<md-grid-list cols="3" rowHeight="fit">...`
+
+Defaults to a 1:1 ratio of width:height. 
+        
+####`gutterSize`
+
+Gutter size can be set to any `px`, `em`, or `rem` value with the `gutterSize` property.  If no 
+units are specified, `px` units are assumed.
+
+Ex: `<md-grid-list cols="3" gutterSize="4px">...`
+
+Defaults to `1px`.
+        
+## Grid tile config
+
+You can set the rowspan and colspan of each tile individually, using the `rowspan` and `colspan` 
+properties.  If not set, they both default to `1`.
+
+```html
+<md-grid-list cols="4" rowHeight="100px">
+  <md-grid-tile *ngFor="let tile of tiles" [colspan]="tile.cols" [rowspan]="tile.rows"
+  [style.background]="tile.color">
+    {{tile.text}}
+  </md-grid-tile>
+</md-grid-list>
+```
+
+```javascript
+...
+export class MyComp {
+  tiles: any[] = [
+    {text: 'One', cols: 3, rows: 1, color: 'lightblue'},
+    {text: 'Two', cols: 1, rows: 2, color: 'lightgreen'},
+    {text: 'Three', cols: 1, rows: 1, color: 'lightpink'},
+    {text: 'Four', cols: 2, rows: 1, color: '#DDBDF1'},
+  ];
+}
+```
+
+Output:
+
+<img src="https://material.angularjs.org/material2_assets/grid-list/fancy-grid-list.png">
+
+## TODO
+
+- Grid tile headers and footers
+- Responsive sizing support