Additionally the dependencies for GNRC specific modules are centralized in Makefile.dep.

With the previous commit TLSF should compile for native, too.

The init function was patched out, but is actually required to compile without warnings with -pedantic enabled.

This patch also updates ccn-lite and x86 support accordingly.

As discussed in #2725, this commit renames a number of stacksize constants to
better convey their intended usage. In addition, constants for thread priority
are given a `THREAD_` prefix. Changes are:

* KERNEL_CONF_STACKSIZE_PRINTF renamed to THREAD_EXTRA_STACKSIZE_PRINTF
* KERNEL_CONF_STACKSIZE_DEFAULT renamed to THREAD_STACKSIZE_DEFAULT
* KERNEL_CONF_STACKSIZE_IDLE renamed to THREAD_STACKSIZE_IDLE
* KERNEL_CONF_STACKSIZE_MAIN renamed to THREAD_STACKSIZE_MAIN
* Move thread stacksizes from kernel.h to thread.h, since the prefix changed
* PRIORITY_MIN renamed to THREAD_PRIORITY_MIN
* PRIORITY_IDLE renamed to THREAD_PRIORITY_IDLE
* PRIORITY_MAIN renamed to THREAD_PRIORITY_MAIN
* Move thread priorities from kernel.h to thread.h since the prefix has changed
* MINIMUM_STACK_SIZE renamed to THREAD_STACKSIZE_MINIMUM for consistency

Removes the old interface.

Please see #1715.
Closes #1715.

This PR implements the new Makefile variables "FEATURES_PROVIDED" and
"FEATURES_REQUIRED". A board *can* have a new file `Makefile.features`
which looks like:

```make
FEATURES_PROVIDED = transceiver
```

An application can have a corresponding line

```make
FEATURES_REQUIRED = transceiver
```

If the selected BOARD does not fulfil the requirements of the
application, then a *warning* is issued at compile time.

This change only includes the feature "transceiver", further features
are expected to be listed in further PRs. The requirement "transceiver"
is automatically added if the application uses the module
"defaulttransceiver".

`make buildtest` understands the new feature listing, so the user won't
need to add boards to `BOARD_BLACKLIST` manually.

Part of the change are the added Make targets
* `info-features-missing`, which prints the required features
  `\setminus` the provided features. The output is empty if there are no
  features missing.
* `info-boards-features-missing`, the same as `info-features-missing`
  but as a table for all boards, but heeded `BOARD_WHITELIST` and
  `BOARD_BLACKLIST`.

Applications don't have to use this new feature. This change does not
break existing Makefile.

Some variables had multiple definitions, but could be removed or
declared with a smaller scope.

Instead of using differing integer types use kernel_pid_t for process
identifier. This type is introduced in a new header file to avoid
circular dependencies.

The correct stack size for all examples and test applications correctly.
KERNEL_CONF_STACKSIZE_MAIN is the correct stack size for any thread
using printf.

Also adapted black lists accordingly.

Fixes #1138

fixes #548

Currently this works only in qemu.