While it's generally frowned upon testing privates, it can often be
useful and the easier way to write tests. Eg you want to test something
complicated method that is important, but you do not want to expose it
directly to other classes...

This new method uses reflection to make access to such methods possible
from within tests without the need for intermediate classes.

We still need 5 to test on old php versions, but travis uses 6 for newer
PHP versions (and 5 may break on those).

Luckily both versions aren't that far apart, yet. This adds a thin
adapter class when running on 6.

However those classes are already supported in PHP 5.7 so we can switch
to them without breaking backward-compatibility.

Some of our tests require that at least one second has passed before
they can continue because our revisions depend on the Unix Timestamp.

Currently we use a sleep(1) for this. However this always waits a whole
second, even if the next second is already much closer or maybe already
here - especially when some processing has been done since the last
operation.

This new method waits for the next second by checking the time every
10th of a second. This might speed up some of our tests a bit.

getMock is deprecated in new PHPUnit versions and createMock is the
recommended replacement. However that one is not available in older
PHPUnit releases. Since we still support older PHP releases we have to
support older PHPUnit releases as well.

This add some compatibility functions to our TestCase class and replaces
all calls to getMock. Tested with PHPUnit 4.6.6 and 5.5.0.

In an older version of PHP a file_exists() call would issue a warning
when the file did not exist. This was fixed in later PHP releases. Since
we require PHP 5.3 now, there's no need to supress any error here
anymore. This might even give a minor performance boost.

Mostly this is for unit tests which use of \$_SERVER['REMOTE_USER']

It ensures the reference/alias connection between \$INPUT->server
and \$_SERVER is renewed before each test.  Tests using TestRequest
class will replace this \$INPUT with their own.

There's still more that I'd like to moved out. bootstrap should not
contain any logic but only call the appropriate functions for setup the
test environment.