Restructure modules

Modules are now separated into a fashion where the library can be used
for most use cases, without needing to compile the rest.

The core of serenity, with no features enabled, contains only the
struct (model) definitions, constants, and prelude. Models do not have
most functions compiled in, as that is separated into the `model`
feature.

The `client` module has been split into 3 modules: `client`, `gateway`,
and `http`.

`http` contains functions to interact with the REST API. `gateway`
contains the Shard to interact with the gateway, requiring `http` for
retrieving the gateway URL. `client` requires both of the other features
and acts as an abstracted interface over both the gateway and REST APIs,
handling the event loop.

The `builder` module has been separated from `utils`, and can now be
optionally compiled in. It and the `http` feature are required by the
`model` feature due to a large number of methods requiring access to
them.

`utils` now contains a number of utilities, such as the Colour struct, the
`MessageBuilder`, and mention parsing functions.

Each of the original `ext` modules are still featured, with `cache` not
requiring any feature to be enabled, `framework` requiring the `client`,
`model`, and `utils`, and `voice` requiring `gateway`.

In total the features and their requirements are:

- `builder`: none
- `cache`: none
- `client`: `gateway`, `http`
- `framework`: `client`, `model`, `utils`
- `gateway`: `http`
- `http`: none
- `model`: `builder`, `http`
- `utils`: none
- `voice`: `gateway`

The default features are `builder`, `cache`, `client`, `framework`,
`gateway`, `model`, `http`, and `utils`.

To help with forwards compatibility, modules have been re-exported from
their original locations.

1 files changed, 4 insertions, 5 deletions

diff --git a/src/utils/mod.rs b/src/utils/mod.rs
index ec19ff7..6ae937e 100644
--- a/src/utils/mod.rs
+++ b/src/utils/mod.rs
@@ -1,17 +1,16 @@
 //! A set of utilities to help with common use cases that are not required to
 //! fully use the library.
 
-#[macro_use]
-pub mod macros;
-
-pub mod builder;
-
 mod colour;
 
 mod message_builder;
 
 pub use self::colour::Colour;
 
+// Note: Here for BC purposes.
+#[cfg(feature="builder")]
+pub use super::builder;
+
 use base64;
 use std::ffi::OsStr;
 use std::fs::File;