reset spatial filter when no bounding box given
Accept datetime.date objects when field type is 'date'
Merge pull request #129 from rbuffat/fix_filter2

reset spatial filter when no bounding box given
Test for #129.
Merge pull request #130 from lordi/accept-date-objects

Accept datetime.date objects when field type is 'date'
Merge pull request #128 from rbuffat/master

add support for slice
Add stop and start arguments to filter()

And friends. See #132.
Merge pull request #133 from Toblerity/issue123

Add stop and start arguments to filter()
refactor Iterator __next__()
add support for a mask geometry as spatial filter
destroy geometry after filter is set
Merge pull request #136 from rbuffat/geometryfilter

add geometry based spatial filter
Merge pull request #135 from rbuffat/slice

refactor Iterator __next__()