Drawing boundaries feature refactoring

[coveralls]

Pull Request Test Coverage Report for Build 1486

• 2 of 25 (8.0%) changed or added relevant lines in 2 files are covered.
• 2 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.4%) to 42.579%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
library/src/main/java/io/ona/kujaku/manager/SplittingManager.java	1	8	12.5%
library/src/main/java/io/ona/kujaku/manager/DrawingManager.java	1	17	5.88%
<!--	Total:	2	25	8.0%	-->

Files with Coverage Reduction	New Missed Lines	%
library/src/main/java/io/ona/kujaku/manager/DrawingManager.java	2	81.5%
<!--	Total:	2		-->

Totals
Change from base Build 1483:	0.4%
Covered Lines:	2295
Relevant Lines:	5390

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💛 - Coveralls

[ekigamba]

@eotin Update this branch and make sure coveralls is OK. When this PR is merged, we can merge the other PR. This PR is smaller and should not take long to approve