Dependencies to fix broken collectstatic

The `collectstatic` command is currently broken as it is trying to use certain keyword arguments that are not supported by the latest version of `django-pipeline`.

Because the requirement for `django-pipeline` is defined as `>=` in `setup.py` it brings in the latest version (as of this writing 1.2.15) although ReviewBoard is known to work with version 1.2.1. 

This pull request fixes this problem (traceback cut off for brevity) by setting the requirement to 1.2.1 strict:

    ...
    File "/opt/devel/rboard/lib/python2.6/site-packages/django_pipeline-1.2.15-py2.6.egg/pipeline/compilers/__init__.py", line 41, in compile
        compiler.compile_file(infile, outfile, outdated=outdated, force=force)
    TypeError: compile_file() got an unexpected keyword argument 'outdated'  

The next problem is that `jsmin` doesn't get installed because it is not defined anywhere as a dependency so I included that into the requirements, the
latest version (2.0.2) seemed to work correctly and finally was able to compile absolutely everything that ReviewBoard needs to work. The error that 
that fix prevents is below (again, traceback cut for brevity):

    ...
    File "/opt/devel/rboard/lib/python2.6/site-packages/pipeline/compressors/jsmin/__init__.py", line 10, in compress_js
      from jsmin import jsmin
     ImportError: No module named jsmin