New command podfile-info - Shows information on installed Pods #855

Usage:
```
    $ pod podfile-info [PODFILE_PATH]

      Shows information on installed Pods in current Project. 
      If optional `PODFILE_PATH` provided, the info will be shown for
      that specific Podfile

Options:
    --md         Output information in Markdown format
```

Sample output:

```
Pods used:

- AFNetworking - A delightful iOS and OS X networking framework.
- DCIntrospect - Introspect is small set of tools for iOS that aid in debugging user interfaces built with UIKit.
```