BUG: Require geopy 0.96 in test requirements

Changes in 0.97 break GeoPandas error detection. Until this is properly
handled, this fixes the Travis build.
ENH: First commit at common class for geo ops

Moves the GeoSeries geo-aware ops into a base GeoPandas class.
And gets all tests passing
Enable geometry methods on GeoDataFrame

GeoDataFrame is geometry-enabled by inheriting from GeoPandasBase.
The GeoPandasBase operations get the geometry property from the input.

Move __contains__ back to GeoSeries.
Fixes for calling geometry propery on inputs

Properly calls _geo_op and _series_op getting the 'geometry' property
on all inputs
Move tests to test_geom_methods.py

For geometry tests, test both the GeoSeries and GeoDataFrame versions.

If the method's input is also a GeoSeries, test the input for both
GeoSeries and GeoDataFrame as well.

For example, for intersects(), test the following combination of inputs:
GeoSeries, GeoSeries,
GeoDataFrame, GeoSeries,
GeoSeries, GeoDataFrame,
GeoDataFrame, GeoDataFrame

Helper functions are provided to test all combinations
Move overloaded operators to GeoSeries
Rename equals methods to geom_equals

Renames on GeoPandasBase:
* equals() -> geom_equals()
* almost_equals() -> geom_almost_equals()
* equals_exact() -> geom_equals_exact()
Re-enable operator overload tests for GeoSeries.
Merge pull request #80 from jwass/geopy096

BUG: Require geopy 0.96 in test requirements
Merge pull request #68 from jwass/gdfops

Geometry Operations on GeoDataFrame
Remove the shift = translate alias

Over-riding shift on GeoSeries and GeoDataFrame clobbered shift
in Pandas. Get rid of it and just use translate
Add from_features constructor for GeoDataFrame.

Allows passing a list of features or objects that implement
__geo_interface__ for easier GeoDataFrame construction.
Merge pull request #82 from jwass/no_shift

Remove the shift = translate alias
Merge pull request #83 from jwass/from_features

Add from_features constructor for GeoDataFrame.
TST: Add pandas release 0.13 to travis test matrix
Merge pull request #84 from kjordahl/test/pandas-0.13

Add pandas release 0.13 to Travis CI tests
TST: Add coveralls to test requirements
TST: Run coveralls on travis
TST: Use py.test with pytest-cov to run tests for better coverage support
TST: Let's not test the whole world