Justin Ely pointed out a regression where previously it was possible to pass in something like format='f4' to the Column initializer, indicating that a single precision float column should be created (presumably for a binary table, at least by default).  The fact that this even worked before only further compounds the confusion over the 'format' argument, but I didn't intend to cause a regression on this behavior, and who knows how much code is out there that depends on it.  This adds still more sophistication to the column format guessing scheme, and fixes a few other issues that arose when I wrote regression tests covering the previous behavior.  This also reverts the change I (likely sleepily) made to the tests in 43c6162c48083fbf1d48757849da588348df6ab3, which allowed binary tables to be written with format codes for character columns like 'A10' (for 10 character strings).  The proper format, per the FITS standard, should always be '10A'.  Although the Column constructor allows both forms, only the '10A' form should be written.  I couldn't find *any* FITS documentation suggesting flexibility in this matter (the closes I could find is the substring array convention: http://fits.gsfc.nasa.gov/registry/substring.html, but that has never been supported by PyFITS).

git-svn-id: http://svn6.assembla.com/svn/pyfits/trunk@2345 ed100bfc-0583-0410-97f2-c26b58777a21

Conflicts:

	astropy/io/fits/tests/test_table.py
Added documentation for the new support of pseudo-unsigned integer columns to the changelog

git-svn-id: http://svn6.assembla.com/svn/pyfits/trunk@2346 ed100bfc-0583-0410-97f2-c26b58777a21
Merge pull request #1770 from embray/fits-merge

Fix for regression in pyfits on column format support
Some formatting fixes for the changelog. Most of this is extremely pedantic--I've always tried to place references to issue numbers outside periods, not inside.  Also removed reference to issue #1343 since it's not a fix against 0.2.x
Added changelog entries for the first batch of undocumented new features and fix
Added as many undocumented changes against v0.2.x as I could find.  Still probably not 100% exhaustive, but close...
Spelling fixes
Remove a few refs that don't actually reference any API objects. There are a few other refs that do but that are not being linkified--not sure why, but I'm not going to worry about that for now.
First round of relocating inline imports; this specifically focuses on modules that are already imported, in general, when you first start the Python interpreter. So in most cases there's not much point in burying them in function calls because those modules are guaranteed to always be imported to begin with.
Phase 2: This moves inline imports of any standard library modules that are guaranteed to be imported during 'import astropy' regardless, and don't in general make sense to have as inline imports.  Numpy is included in this as well, though there are a few places where Numpy shouldn't be imported (such as in modules that might be imported at setup-time when Numpy might not be installed). There are few other exceptions too, but not many.
Updated a couple modules to be just importable enough on Python 3 to display a new error message when trying to import astropy from within the source checkout with Python 3.
Add module references in sphinx for utils and vo

This just makes it slightly easier to deal with linking to these packages in sphinx and intersphinx

[ci skip]
Removes some more unused imports that were found with pylint. I don't *think* this breaks anything but I'll be interested to see what the CI systems say
Clarified that support for running the tests in the Sphinx docs is
not integrated *yet* but will be soon.
Merge pull request #1778 from embray/changelog-0.3

Changelog 0.3
be smarter about how find_api determines the version
Expand getting started and include mention of find_api_page
include find_api_page in top-level
fix find_api_page for py3
Add mention that `find_api_page` is at the top-level of the package