fix DateEncoderTest

assertSequenceEqual somehow does not work as I expected, use (array1 == array2).all() instead
some imports, etc..
fix CategoryEncoderTest
fixes AdaptiveScalarTest
DeltaEncoder unit tests
unit tests for LogEncoder
rename log.py to logenc.py to avoid name conflict

with math.log
remove unused variables in scalar encoder
ScalarEncoder unit tests
tests for scalar-space encoder
SDRRandomEncoder tests
SDRCategory enc test
test NonUniformScalarEncoder
MultiEncode test
prune __init__