UnicodeFuzzySearch: Add parenthesis around the function call.

`chr` or `hex` was eating up everything in the function and treating them all as parameters. Because of that, it results into:

```perl
{
    symbol => "...",
}
```

Instead of:

```perl
{
    symbol => "...",
    code => "...",
    name => "...",
}
```
Fix USPS URL

The current URL used is seemingly no longer valid.
Conversions: Fixing issue #552
Update checklist with new links and code styleguide
Merge pull request #559 from PhantomGamers/master

Fix USPS URL
Merge pull request #557 from duckduckgo/jag/unicode

UnicodeFuzzySearch: Add parenthesis around the function call.
Merge pull request #563 from duckduckgo/mintsoft/convert-fixes

Conversions: Fixing issue #552