Add "compile everything" tool

Having many tests is quite futile if they aren't executed once in a
while<sup>[citation needed]</sup>.

Alas, this is not the purpose of this PR. This PR adds the tool
"compile_test.py", which executes `make buildtest` for all applications
in `examples` and `tests`, and prints a comprehensive list of the
results.

dist/tools/compile_test/compile_test.py

+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+
+# Copyright (C) 2014  René Kijewski  <rene.kijewski@fu-berlin.de>
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+
+from __future__ import print_function
+
+from itertools import groupby, ifilter, imap
+from os import devnull, environ, listdir
+from os.path import abspath, dirname, isdir, join
+from subprocess import PIPE, Popen
+from sys import exit
+
+riotbase = environ.get('RIOTBASE') or abspath(join(dirname(abspath(__file__)), '../' * 3))
+
+null = open(devnull, 'w')
+
+success = []
+failed = []
+exceptions = []
+
+for folder in ('examples', 'tests'):
+    print('Building all applications in: \033[1;34m{}\033[0m'.format(folder))
+    for application in sorted(listdir(join(riotbase, folder))):
+        if not isdir(join(riotbase, folder, application)):
+            continue
+
+        print('\tBuilding application: \033[1;34m{}\033[0m'.format(application))
+        try:
+            subprocess = Popen(('make', 'buildtest'),
+                               stdout=PIPE,
+                               stderr=null,
+                               cwd=join(riotbase, folder, application))
+            lines = imap(str.rstrip, subprocess.stdout)
+            lines = ifilter(bool, lines)
+            lines = imap(lambda s: s.split(' .. '), lines)
+            lines = ifilter(lambda t: len(t) == 2, lines)
+            lines = imap(lambda (board, outcome): (outcome, board[len('Building for '):]), lines)
+            lines = groupby(sorted(lines), lambda (outcome, board): outcome)
+            for group, results in lines:
+                print('\t\t{}: {}'.format(group, ', '.join(sorted(board for outcome, board in results))))
+
+            returncode = subprocess.wait()
+            (failed if returncode else success).append(application)
+        except Exception, e:
+            print('\t\tException: {}'.format(e))
+            exceptions.append(application)
+        finally:
+            try:
+                subprocess.kill()
+            except:
+                pass
+
+print('Outcome:')
+for color, group, applications in (('2', 'success', success), ('1', 'failed', failed), ('4', 'exceptions', exceptions)):
+    if applications:
+        print('\t\033[1;3{}m{}\033[0m: {}'.format(color, group, ', '.join(applications)))
+
+if exceptions:
+    exit(2)
+elif failed:
+    exit(1)
+else:
+    exit(0)