Add implementatin of box filter and blur

[miralshah365]

Description

implemented blur function

tests added for box_filter

This utility will provide a way to remove noise from the image using convolution with average kernel(normalized and unnormalized).

It also provides blur function which works only with normalized mean kernels

References

closes #382

Tasklist

• Add test case(s)
• Ensure all CI builds pass
• Review and approve

[mloskot]

@miralshah365 LGTM. Feel free to merge.

There is an important build configuration missing

[mloskot]

run box_filter.cpp ; entry is missing from here:

gil/test/core/image_processing/Jamfile

Line 17 in ec30419

run threshold_binary.cpp ;

Currently, the box_filter.cpp test is not compiled on Jamfile-only CI jobs on Travis CI and AppVeyor.

[mloskot]

@miralshah365 There is one request for change to fix the test linking error

[mloskot]

@miralshah365 looks good, feel free to merge.

Looks like you'll need to resolve conflict