Update multithread.py
Merge pull request #235 from joshuasims/patch-2

Update multithread.py
mark - changes to converter to not load value in file_only situations
mark - added dir_output option to compute
mark - changes to variable adding support for fill_value and dtype at init
mark - dtype and fill_value now read from metadata
mark - before messing with sample size - going to be an issue!
mark - before assessing dtype loading issue
mark - before addressing south dakota
i242: adjacent geometries result in subset error when output requires wrapping

A deepcopy was introduced before a the spatial dimension is wrapped.
The reference to the base field was being updated resulting in adjacent
geometries throwing subset errors.

Closes #242.
Merge branch 'master' into large-array-testing
mark - before merging seasonal branch
Merge branch 'i155-seasonal' into large-array-testing
mark - fixed climatology bounds writing and reading
Merge branch 'i-climatology-bounds' into large-array-testing

Conflicts:
	src/ocgis/conv/nc.py
mark - test_bad_keywords working
mark - before adding get_dtype to access dtype
mark - all tests working