TST: remove yields in coordinate_system tests

Remove use of generators in tests to make them easier to debug
RF: allow object coordinate in coordinate system

Objects as coordinate values can be useful for sympy expressions as
coordinates.  Objects can often be subtracted, compared etc.  In fact we
already use objects as a coordinate type in the documentation.
RF: allow coordinate map to work with object dtype

Coordinate maps can sensibly have object dtypes in the coordinate
system, such as sympy symbols.  Take these into account for inverses,
permutations.

The inverse of an AffineTransform previously could have a different
coordinate input / output type from the original.  Constrain to have the
same coordinate types, return None for inverse otherwise.

Adapt the doctest for __call__ to reflect this.
BF: allow CoordinateMap subclasses on L & R of ==

We were previously only testing subclasses in one direction, but a
subclass on the left or the right should be OK.  Test.
RF: refactor to restore previous inverse behavior

Restore the previous behavior of returning a floating point inverse
(mostly) from an int input AffineTransform.  Add flag to inverse method
to specify new behavior of returning None when no integer inverse can be
found.
BF: fix travis yml file for build errors

Travis seems to be timing out for the slow tests now.  Run the not slow
tests only.

The sympy build command was not correct and it has probably been
building the master up until now.  Fix to build the latest release.
[BF] Fix bug in multiple_fast_inv.

Some computations were done outside the loop, but they depend
on values changing at each iteration.
Merge pull request #248 from matthew-brett/allow-object-coordinates

Allow object coordinates in CoordinateSystem and CoordinateMap
Add test for multiple_fast_inv.

That test would fail with earlier versions of the routine.
Cosmit: Syntax simplification in multiple_fast_inv.

This helps better understanding what is the code logic.
I do not think it can be further factorized yet.
Merge pull request #249 from VirgileFritsch/master

BF: Fix bug in multiple_fast_inv

Some computations were done outside the loop, but they depend on values changing at each iteration. This resulted in wrong inverse values because of the use of the wrong piv variable. Also the check of info was done only for the last decomposition.
FMRILinearModel handles the case where contrasts are null for some fmri sessions
Syntax change in FMRILinearModel.contrast implementation
Added test in test_glm.test_high_level_glm_null_contrasts and fixed a glitch in test_glm.generate_fake_fmri_data
Removed useless contrast in test_glm.test_high_level_glm_null_contrasts
Merge branch 'glm_null_contrasts_rerebased' into main-master

* glm_null_contrasts_rerebased:
  Removed useless contrast in test_glm.test_high_level_glm_null_contrasts
  Added test in test_glm.test_high_level_glm_null_contrasts and fixed a glitch in test_glm.generate_fake_fmri_data
  Syntax change in FMRILinearModel.contrast implementation
  FMRILinearModel handles the case where contrasts are null for some fmri sessions
DOC: working out windows compiles

Not yet compiling on windows 64-bit, working notes for trying to do this.
NF: tool to refresh modification time of C files

Build step checks modification times of C files relative to their source
Pyx files.  git checkout on windows sometimes generates C files that are
detectably earlier in modification time than the pyx files, so the build
step tries to rebuild them using Cython.  This utility touches the C
files to set the modification time later than the pyx files.
RF: replace numpy.testing.assert_ with assert_true

numpy.testing.assert_ appeared in numpy 1.3.  That's pretty old, but
it's the only thing stopping us being compatible with numpy 1.2, and
nose assert_true is just as readable.
RF: no dict methods for old numpy load returns

Older numpies (at least up until 1.3) return a dict-like thing from
``np.load`` on an ``npz`` file, but without an ``items`` method or other
helpful iteration stuff.  Fall back to the ``files`` attribute on the
returned object to find the first and only array to get the design
matrix.