python3 installation support

this fixes the issue while installing for Python3:

```
$ pip install django-bootstrap-pagination
Downloading/unpacking django-bootstrap-pagination
  Downloading django-bootstrap-pagination-1.5.0.tar.gz
  Running setup.py (path:/Volumes/Data/Users/miki725/.virtualenvs/test-py3/build/django-bootstrap-pagination/setup.py) egg_info for package django-bootstrap-pagination
    Traceback (most recent call last):
      File "<string>", line 17, in <module>
      File "/Volumes/Data/Users/miki725/.virtualenvs/test-py3/build/django-bootstrap-pagination/setup.py", line 26, in <module>
        "License :: OSI Approved :: MIT License",
      File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/distutils/core.py", line 148, in setup
        dist.run_commands()
      File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/distutils/dist.py", line 955, in run_commands
        self.run_command(cmd)
      File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/distutils/dist.py", line 974, in run_command
        cmd_obj.run()
      File "<string>", line 14, in replacement_run
      File "/Volumes/Data/Users/miki725/.virtualenvs/test-py3/lib/python3.4/site-packages/setuptools/command/egg_info.py", line 322, in write_pkg_info
        metadata.write_pkg_info(cmd.egg_info)
      File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/distutils/dist.py", line 1108, in write_pkg_info
        self.write_pkg_file(pkg_info)
      File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/distutils/dist.py", line 1129, in write_pkg_file
        long_desc = rfc822_escape(self.get_long_description())
      File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/distutils/util.py", line 470, in rfc822_escape
        lines = header.split('\n')
    TypeError: Type str doesn't support the buffer API
    Complete output from command python setup.py egg_info:
    running egg_info

creating pip-egg-info/django_bootstrap_pagination.egg-info

writing dependency_links to pip-egg-info/django_bootstrap_pagination.egg-info/dependency_links.txt

writing pip-egg-info/django_bootstrap_pagination.egg-info/PKG-INFO

Traceback (most recent call last):

  File "<string>", line 17, in <module>

  File "/Volumes/Data/Users/miki725/.virtualenvs/test-py3/build/django-bootstrap-pagination/setup.py", line 26, in <module>

    "License :: OSI Approved :: MIT License",

  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/distutils/core.py", line 148, in setup

    dist.run_commands()

  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/distutils/dist.py", line 955, in run_commands

    self.run_command(cmd)

  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/distutils/dist.py", line 974, in run_command

    cmd_obj.run()

  File "<string>", line 14, in replacement_run

  File "/Volumes/Data/Users/miki725/.virtualenvs/test-py3/lib/python3.4/site-packages/setuptools/command/egg_info.py", line 322, in write_pkg_info

    metadata.write_pkg_info(cmd.egg_info)

  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/distutils/dist.py", line 1108, in write_pkg_info

    self.write_pkg_file(pkg_info)

  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/distutils/dist.py", line 1129, in write_pkg_file

    long_desc = rfc822_escape(self.get_long_description())

  File "/usr/local/Cellar/python3/3.4.2_1/Frameworks/Python.framework/Versions/3.4/lib/python3.4/distutils/util.py", line 470, in rfc822_escape

    lines = header.split('\n')

TypeError: Type str doesn't support the buffer API

----------------------------------------
Cleaning up...
Command python setup.py egg_info failed with error code 1 in /Volumes/Data/Users/miki725/.virtualenvs/test-py3/build/django-bootstrap-pagination
Storing debug log for failure in /Volumes/Data/Users/miki725/.pip/pip.log
```