Make code pep8 compliant

In this pull request, the code (excluding the tests) is made [pep8](http://www.python.org/dev/peps/pep-0008/) compliant.
I've used the tool [pep8 - Python style guide checker](https://github.com/jcrocholl/pep8).
You can install it with the command `pip install pep8`.

Existing code:
```
shell> pep8 . --exclude=ghtTests/
./gtrial.py:5:1: W293 blank line contains whitespace
./gtrial.py:12:1: E302 expected 2 blank lines, found 1
./gtrial.py:15:21: E225 missing whitespace around operator
./gtrial.py:16:1: W293 blank line contains whitespace
./gtrial.py:21:1: W293 blank line contains whitespace
./gtrial.py:22:1: E302 expected 2 blank lines, found 1
./gtrial.py:24:6: E225 missing whitespace around operator
./gtrial.py:25:1: W293 blank line contains whitespace
./gtrial.py:27:1: W293 blank line contains whitespace
./gtrial.py:31:1: W293 blank line contains whitespace
./gtrial.py:33:1: W293 blank line contains whitespace
./gtrial.py:37:1: W293 blank line contains whitespace
./gtrial.py:41:1: W391 blank line at end of file
./qt4reactor.py:12:1: W293 blank line contains whitespace
./qt4reactor.py:48:80: E501 line too long (87 > 79 characters)
./qt4reactor.py:51:80: E501 line too long (88 > 79 characters)
./qt4reactor.py:74:5: E303 too many blank lines (2)
./qt4reactor.py:82:5: E303 too many blank lines (2)
./qt4reactor.py:86:80: E501 line too long (89 > 79 characters)
./qt4reactor.py:87:9: E301 expected 1 blank line, found 0
./qt4reactor.py:101:47: E261 at least two spaces before inline comment
./qt4reactor.py:101:80: E501 line too long (97 > 79 characters)
./qt4reactor.py:109:9: E301 expected 1 blank line, found 0
./qt4reactor.py:112:1: W293 blank line contains whitespace
./qt4reactor.py:127:1: E303 too many blank lines (3)
./qt4reactor.py:140:22: E225 missing whitespace around operator
./qt4reactor.py:141:25: E225 missing whitespace around operator
./qt4reactor.py:144:25: E225 missing whitespace around operator
./qt4reactor.py:149:5: E303 too many blank lines (2)
./qt4reactor.py:160:5: E303 too many blank lines (2)
./qt4reactor.py:167:5: E303 too many blank lines (2)
./qt4reactor.py:174:5: E303 too many blank lines (2)
./qt4reactor.py:185:1: W293 blank line contains whitespace
./qt4reactor.py:186:5: E303 too many blank lines (2)
./qt4reactor.py:193:5: E303 too many blank lines (2)
./qt4reactor.py:200:5: E303 too many blank lines (2)
./qt4reactor.py:208:5: E303 too many blank lines (2)
./qt4reactor.py:212:5: E303 too many blank lines (2)
./qt4reactor.py:216:5: E303 too many blank lines (2)
./qt4reactor.py:216:23: E231 missing whitespace after ','
./qt4reactor.py:217:31: E231 missing whitespace after ','
./qt4reactor.py:222:5: E303 too many blank lines (2)
./qt4reactor.py:226:1: W293 blank line contains whitespace
./qt4reactor.py:228:5: E303 too many blank lines (2)
./qt4reactor.py:237:80: E501 line too long (89 > 79 characters)
./qt4reactor.py:238:1: W293 blank line contains whitespace
./qt4reactor.py:255:5: E303 too many blank lines (2)
./qt4reactor.py:260:5: E303 too many blank lines (2)
./qt4reactor.py:274:1: W293 blank line contains whitespace
./qt4reactor.py:275:5: E303 too many blank lines (2)
./qt4reactor.py:282:5: E303 too many blank lines (2)
./qt4reactor.py:290:5: E303 too many blank lines (2)
./qt4reactor.py:295:80: E501 line too long (90 > 79 characters)
./qt4reactor.py:308:5: E303 too many blank lines (2)
./qt4reactor.py:318:1: W293 blank line contains whitespace
./qt4reactor.py:319:5: E303 too many blank lines (2)
./qt4reactor.py:324:5: E303 too many blank lines (2)
./qt4reactor.py:352:80: E501 line too long (81 > 79 characters)
./qt4reactor.py:359:1: W391 blank line at end of file
./setup.py:10:12: E225 missing whitespace around operator
./twisted/plugins/qt4.py:9:1: W391 blank line at end of file
```

In this branch:
```
shell> pep8 . --exclude=ghtTests/
shell>
```