Removed type `Range`. function `math.range` now returns an expanded series
First implementation of Index and math.index
Removed the subset functionality from Index, makes more sense to put that in Matrix
Index functionality getting in place now.
Merge remote-tracking branch 'origin/develop' into develop

Conflicts:
	test/function/matrix/squeeze.test.js
	test/function/matrix/subset.test.js
Adjusted tests for new Index
Made math.subset, Matrix.get, Matrix.set more strict: only accept an Index
Examples and docs updated
Fixed matrix.get and matrix.set examples in readme
Merge remote-tracking branch 'origin/develop' into develop

Conflicts:
	test/function/utils/select.test.js
	test/type/matrix.test.js
	test/type/range.test.js
Fixed failing unit tests
Merge branch 'develop' into index