RF - use relative imports in kernel_smooth tests
TST - basic smoke test for kernel smooth
BF+TST - fix shape error for kernel_smooth

kernal smooth was using the wrong (input) coordmap size to reshape the
real points kernel array.  Fix plus tests for behavior with and without
rotation.
cosmit in graph/field
COSMIT: variable renaming in graph
Significant speed up in hroi merge
Significant speed up in bifurcations code
ENH: A bit of cleaning in the watershed/blobs examples
cosmit
DOC: add commit codes listing

with example commit message and some explanation.
DOC: update codes from feedback

NF -> ENH.  Remove PL in favor of STY.  Add WIP and comment on using WIP
for pull request comments.
Merge pull request #138 from matthew-brett/commit-codes

DOC: add commit codes listing
FIX viz: computing bounds with empty plot
TEST viz: test empty plots
array sizes match now
testcase for masked datasets
Masked registration test.
COSMIT on docstrings in field module
ENH: changed np.infty to np.inf in the codebase
Fixed the issue raised by Satra on FIR models