Fixes #622.  Add methods to look up elements by utype.
Merge pull request #626 from astrofrog/fix-absolute-imports

Fix more absolute imports to relative imports
Remove __new__ for Constant since it was no longer used, and caused issues with Python 3.3
Possible fix for #587; a Unit times a Quantity returns a new Quantity.
Add a simple test for #587, testing the commutativity (or lack thereof) for multiplication and division of Quantities with Units
Merge pull request #603 from astrofrog/fix-constants-python3.3

astropy.constants doesn't import in python3.3
This is a mostly trivial change, but it's also more consistent--if the other unit conversions in this class are using abbreviations why shouldn't lightyear? Alternatively, both versions could be made available (i.e 'lightyear' and 'lyr', likewise 'pc' and 'parsec', etc.)
Merge pull request #616 from astrofrog/fix-setuptools

pip installation fails if distribute version is too old
updated version to 0.3.dev, as 0.2 development now occurs in 0.2.x branch
Merge pull request #498 from eteq/generate-config-at-install

Changes config package to generate a default config file at install and puts it in the users's astropy directory at first import of astropy
This file was merged into the wrong path in cb09f8f0; I already restored the file to its right location in 8a892b51 but it still hung around here.
This file was merged into the wrong path in cb09f8f0; I already restored the file to its right location in 8a892b51 but it still hung around here.
Add WMAP9 cosmology.

* Add 9 year WMAP cosmology from Hinshaw et al. 2012 (arXiv 1212.5226).
* Because this paper is on arXiv and not yet refereed/published, leave
  WMAP7 as the default.
* Add a WMAP9 test to get_current in test.
Merge pull request #498 from eteq/generate-config-at-install

Changes config package to generate a default config file at install and puts it in the users's astropy directory at first import of astropy
Minor fix to parameter values

* Previously, Oc0 was Oc h^2 / h^2, but table 4 actually gives
  Oc0 directly, and it's slightly different.  This is presumably
  due to the vagaries of the actual distributions for h and Oc0 h^2.
added changelog entry for #498
updated changelog version number to reflect current dev version (0.3)
added changelog entry for #498
Add missing ) in source for WMAP9 cosmology.
Got rid of references to './setup.py' per @astrofrog's comments. I still used to just 'setup.py foo' when referencing specific setup.py commands, but wrote out 'python setup.py' when discussing full commands run at the command line.