More generic way to find path of current file.
Added test reading with readEvents().
Some more tests reading from files and file-like objects.
Added test to for duplicate id warnings.
Reading the same event twice works without warnings.
Reset file pointer after isFormat() functions.

This makes sure the isFormat() functions do not move the
file pointer (or equivalent in file like objects) when testing
for the formats. This otherwise can result in some subtle bugs
that can even (in Python 3 due to random dictionary ordering)
in seemingly random ways.
Solved some more subtle issues.

Mostly related to the different ways of inputting data to
the NDK functions.
Removing duplicate test
Some more tests regarding the is_ndk() function.
Added test for missing lines.

In that case that particular event will not be read.
Added test for a file with multiple effects.

Tests that the correct warnings are raised and that other
events are still being read.
Now raises if no event is left after parsing.

Also timestamp "O-0000000..." does no longer raise a
warning. While it is not valid occording to the standard, it
occurs a lot.
Added test case for a new _parse_date_time() function.
Implemented new _parse_date_time() function.

Also adjusted the tests to it. obspy.ndk can now parse
time strings that specify 60 seconds.
Compatibility with Python 2.6