DeviceProxy: fix write_attribute_asynch prints incomplete error stack

Closes #738 (closed)

I found that DeviceProx.write_attribute_asynch was not printing the proper stack due to internally it was calling DeviceProxy.write_attributes_asynch. And both DeviceProxy.write_attributes and DeviceProxy.write_attributes_asynch do not print all stack, only which attribute failed. So I switched DeviceProx.write_attribute_asynch to call the corresponding method in cppTango and now the error stack prints properly.

Also I generalized all "write_[read]_attribute" (single) to use the same convertor of name/configuration parameter to DeviceAttribute. This adds "fast" overload to write_read_attribute(s) methods. And this added to tests.

And I changed signatures of methods, which accept sequences, due to if method siganture is tuple PyCharm highlights when you use it with e.g. list. But for us both are valid...