Uwg

Fix
* Fix old import statement. (4c58ab1ce57e0a402e816280cc294d7380ae1e0b)
* Remove double import of readDOE. (0b56bce2c5d0d2714fe83a621de336220760272a)

Fix
* Change if/else condition to account for 1 soil depth. (ccee23a48b80a2379a7a62add8fd7e18e08adea9)

Documentation
* delete print statement (a6b4ba8723f00188b5c9c4221036372e3bd9045b)
* switch example documentation to singapore. (836787e1ee763c267b59708c55278604c8a29cdd)

Fix
* inform user of what input is incorrect (7257cf65b3ad9d215029f6ce0cc355a24c5f895f)

Fix
* add isinstance for all type checking. (c09b8b57e9ac9e3a4256cd7b974452caa8b7bf3c)

Feature
* refactor the required inputs method + tests. (9694fe480461b4ae6a02f569dadbcc8d67ab8e4b)

Fix
* remove latAnth from tests. (05f69dff385ad926df48c0bd24e2e2a150ac9c4e)
* Clean solarcalcs zenith calcs. Make PEP8 compatible. (fecb10e2d065ee5ca1ec696bd32cc78a28ec9c03)

Documentation
* add more checks to the required inputs method tests. (79f2cf89bc0f914c4a7690b4a319476fe04c334a)
* remove latAnth parameter from uwg file. (a92e5d0921bfdedcd81ca816d45da6488ddbd747)

Fix
* replace zenith with self.zenith (99ab63c5318d460c0556ce434b78c4e55591c681)