0.2.3 performance issue

Hi,

I run into a performance issue with 0.2.3 version. 0.2.2 works just fine. Below the sample from profiler output for test function. Also the profiler shows muchbigger output for 0.2.3.

from freezegun import freeze_time
import datetime
def test():
    with freeze_time('2014-10-10'):
        print datetime.datetime.now()

0.2.3:

ncalls  tottime  percall  cumtime  percall filename:lineno(function)
1    0.010    0.010    0.395    0.395 api.py:264(stop)
1    0.009    0.009    0.448    0.448 api.py:223(start)
1    0.000    0.000    0.395    0.395 api.py:220(__exit__)
1    0.000    0.000    0.448    0.448 api.py:217(__enter__)

0.2.2:

ncalls  tottime  percall  cumtime  percall filename:lineno(function)
1    0.001    0.001    0.003    0.003 api.py:223(start)
1    0.001    0.001    0.002    0.002 api.py:255(stop)
1    0.000    0.000    0.002    0.002 api.py:220(__exit__)
1    0.000    0.000    0.003    0.003 api.py:217(__enter__)

[pokidovea]

ping. The problem is urgent. I have about 0.5 sec per api.py:223(start) call. It is called 127 times, so total time is ~1 minute only for freezegun start.

[pokidovea]

I wrote my own simple tool https://github.com/pokidovea/immobilus It works on another principle. it is much faster.