Removed string related functions in VISA (sprintf, queryf, etc)
Removed legacy vpp43
Style changes
Improved set_signature
Started Instrument reorganization into subpackage
Removed deprecated term_chars
Added enum34 as requirement for Python < 3.4
Start creating resources
Implemented Resource class
Implemented MessageBasedResource class.
Implemented SerialResource class.
Implemented GPIB class
Implemented read-only version of properties.
Implemented USB
Implemented USBResource
Implemented RegisterBased class
Changed middle level functions to return the error code
Added _test directory to .gitignore
Removed Legacy docs
Deleted old testsuite and started a new one.
Minor cosmetic improvements.