Add support for forks

Allows package name and OTP application name to differ.

Related to hexpm/hex#40.
Fix botched merge
Add migration setting app on releases and requirements
Fix a bug where pre 0.6.0 clients cannot publish
Show requirements on package page
More robust workaround of Heroku read body

Read request body on all failures. This tries to ensures we respond
from the application instead of getting an Heroku error page because the
connection closed before sending a response.

This is a workaround for a limitation in Heroku who does not consider a
response from the application if the request body was not fully read.
Fix postgres setup instruction

When running migrations for the first time I saw this error:

```
* running UP _build/dev/lib/hex_web/priv/migrations/20140323232653_add_package_downloads_view.exs
* running UP _build/dev/lib/hex_web/priv/migrations/20140510114425_add_installs_table.exs
* running UP _build/dev/lib/hex_web/priv/migrations/20140511133315_add_optional_to_requirements.exs
* running UP _build/dev/lib/hex_web/priv/migrations/20140518153329_add_checksum_to_releases.exs
* running UP _build/dev/lib/hex_web/priv/migrations/20140527204944_change_packages_index_to_trigram.exs
** (Postgrex.Error) ERROR (42501): permission denied to create extension "pg_trgm"
    (ecto) lib/ecto/adapters/postgres/worker.ex:20: Ecto.Adapters.Postgres.Worker.query!/4
    (ecto) lib/ecto/adapters/postgres.ex:337: Ecto.Adapters.Postgres.use_worker/3
    (elixir) lib/enum.ex:537: Enum."-each/2-lists^foreach/1-0-"/2
    (elixir) lib/enum.ex:537: Enum.each/2
    (ecto) lib/ecto/adapters/postgres.ex:473: anonymous fn/3 in Ecto.Adapters.Postgres.migrate_up/3
    (ecto) lib/ecto/adapters/postgres.ex:306: Ecto.Adapters.Postgres.transaction/3
    (ecto) lib/ecto/adapters/postgres.ex:472: Ecto.Adapters.Postgres.migrate_up/3
    (ecto) lib/ecto/migrator.ex:136: anonymous fn/3 in Ecto.Migrator.migrate/3
```

I updated README instructions for setting up postgres to add SUPERUSER permissions for the user.
This way we can create extensions without error.
Log the port that Cowboy starts on

Before it wasn't clear:

```
hex_web[master]% foreman start
12:00:26 web.1  | started with pid 59220
12:00:28 web.1  | [Porcelain]: goon executable not found
12:00:28 web.1  | [Porcelain]: falling back to the basic driver
12:00:28 web.1  |
```

After:

```
hex_web[add_log_for_port]% foreman start
11:59:37 web.1  | started with pid 58891
11:59:38 web.1  | [Porcelain]: goon executable not found
11:59:38 web.1  | [Porcelain]: falling back to the basic driver
11:59:38 web.1  |
11:59:38 web.1  | 2014-10-11 11:59:38.617 [info] Starting Cowboy on port 5000
```
Add note about pgcrypto extension
Display docs on website and API