A hash is stored for each native library with the name libraryName.hash.
If the library is not found on the system search path, it is extracted to a cache directory.
Extracted libraries are named with the hash appended, so the library will not be
re-extracted if one with the same hash already exists.
Hashing without the hash file requires double traversing if the file is not in the cache,
but it is still faster than creating a new file in most cases. This won't be needed
after opencv is updated to provide a hash as well.
I don't have a good way to ensure this always works, so this is going to be a documentation issue.
But initializeHardwareConfiguration is now reentrant, so we can just have all tests call it.
Making Travis run wpilibj_frcnetcomm.py will help avoid bitrot in
FRCNetComm.java in the future. Formatting was also enabled on Python
source files and FRCNetComm.java was added back to the generated files
list.
