removed unused feature in buildslave.scripts.runner.stop()

No code calls stop() with wait flag disabled. Remove wait parameter,
and changed stop() to always wait for the process to finish.
copy StdoutAssertionsMixin class to slave test util package
tests: broke out open() patching code to a mix in class

Created buildslave.test.util.misc.OpenFileMixin class with methods
for patching open() to simulate successful reads and I/O errors.
fixed incorrectly printed message on 'buildslave restart'

Don't print 'no old buildslave process found to stop' when old
slave process was successfully terminated.

Previously stop() returned 'None' when slave was successfully
stoped. To restart() it looked like we failed to stop the slave.

Broke out the code to stop slave into a new stopSlave() utility
function, which will raise an exception if no slave is running.
Use stopSlave() from stop() and restart(), handle the exception
as appropriate for each case.
Merge branch 'slave-restart-msg' of git://github.com/elmirjagudin/buildbot
Monkey patch in synchronous test helpers.

These methods make it easy to test code involving deferreds in a synchronous
and deterministic manner, rather than having to spin the reactor.
Merge branch 'sync-test-helpers' of git://github.com/tomprince/buildbot
Fixed grep command for IRC in log

With grep IRC there is not output from cat on the log file but with grep -i irc there is, see e.g.
```
$ cat master/twistd.log | grep IRC
$ cat master/twistd.log | grep -i irc
2013-04-15 13:26:44+0200 [-] Starting factory <buildbot.status.words.IrcStatusFactory instance at 0x26ab638>
2013-04-15 13:26:58+0200 [IrcStatusBot,client] <buildbot.status.words.IrcStatusBot instance at 0x23ea4d0>: I have joined #buildbot-test
2013-04-15 13:27:29+0200 [-] Starting factory <buildbot.status.words.IrcStatusFactory instance at 0x26b8170>
2013-04-15 13:27:29+0200 [IrcStatusBot,client] not scheduling reconnection attempt
2013-04-15 13:27:29+0200 [IrcStatusBot,client] Stopping factory <buildbot.status.words.IrcStatusFactory instance at 0x26ab638>
2013-04-15 13:27:42+0200 [IrcStatusBot,client] <buildbot.status.words.IrcStatusBot instance at 0x25a10e0>: I have joined #buildbot-test
```
Thus, maybe the example line from the log should be changed too?

I use
Buildbot version: 0.8.6p1
Twisted version: 12.2.0
Merge branch 'master' of git://github.com/Sleft/buildbot
fix typo in gh-pull 693
Fixed inline code and command formatting

Inline code and command formatting should be consistent and clear.
Merge pull request #695 from Sleft/master

Fixed inline code and command formatting
Fixed phrasing and formatted commands and code as such
Fixed inline code and command formatting
Note and warning about distribution specific package managers
Preferred way to install is via pip

To be consistent with the manual
Less repetetive when using synonym

Also fixed command formatting
Fixed link
Merge branch 'master' of git://github.com/Sleft/buildbot
Merge branch 'master' of github.com:buildbot/buildbot