Improving how Trust Lines are displayed

When the Trust Lines are displayed on the page, there is no way to distinguish which trust lines the account has set, and which it has received from other accounts. In addition to this, the trust limit is not included in the table. 

![screen shot 2014-08-26 at 5 49 48 pm](https://cloud.githubusercontent.com/assets/2151492/4053670/9ba58a74-2d7f-11e4-9f08-3dd040167ef1.png)

In order to remedy these two issues, I included the trust limit of the relationship and have split up all Trust Lines into Trust Set by the account and those that were received by the account. In this way, if a trust relationship was both set and received by two accounts, both of those occurrences will be easily identifiable. 

![screen shot 2014-08-26 at 5 52 53 pm](https://cloud.githubusercontent.com/assets/2151492/4053679/b7078a60-2d7f-11e4-9155-60e49e9b9cfc.png)

I have tried to stick with the vocabulary used by the Stellar protocol when naming these two sections but please let me know if anything seems unclear. 
Instead of creating additional state we should just be filtering out account lines that have a 0 limit on both sides.
```js
$scope.account_lines = lines.filter(function(line) {
  return line.limit || line.limit_peer;
});
```