Failure formats exception class names incorrectly in printTraceback

[Jean-Paul Calderone]

It uses safe_str(exceptionClass) instead of qual(exceptionClass). This accidentally worked before Python 2.5 because exception classes str'd to their qual. In Python 2.5 they don't.

[Jean-Paul Calderone]

(In [17394]) Add new-style exception support to Failure

Refs #1858 Refs #1859 Refs #1867

Change the type-checks against ClassType to use inspect.isclass() instead and change the str() of exception types to a qual().

[foom]

(In [17448]) Fix almost all python 2.5 issues.

Merging branches/python-two-point-five-1867.

Authors: mostly exarkun, some jknight Reviewer: jml Closes #1867

In detail:

Fix hashability of three classes in Python 2.5: id() now returns only positive numbers, but no longer always short ints, so returning id(self) as hash breaks. Closes #1842

Truncate mtime and atime floats to be integers in conch's unix sftp server implementation. (They changed to be floats by default in python). The interface is still underspecified. Refs #1860.

Fix Newpb failure handling for new-style exceptions. Use t.p.r.qual to determine exception type names. Closes #1861

Suppress deprecation warning for raising a string exception in test_failure.FailureTestCase.testStringExceptions. Closes #1862

Refactor testPBFailures into multiple test methods to make it easier to debug. Closes #1863

Pass absolute path to interpreter as argv[0] in stdio tests. Using an absolute path lets Python's import machinery figure out what's going on. Closes #1864

Add new-style class support to jelly (absolutely necessary because exceptions are now newstyle classes). Closes #1865

Add new-style exception support to Failure. Closes #1858. Closes #1859.

Fix twisted.python.zipstream to account for the removal of file_offset from the ZipInfo class. Closes #1866.

Use reflect.qual on warning class when logging warnings.