Merge branch 'hotfix/cg_test'
Extract diagonal from DiagonalLinearOperator.
Merge pull request #21 from mpf/patch-1

Extract diagonal from DiagonalLinearOperator.
Add inheritance diags in linop doc.
New CoordLinearOperator.
Tests for CoordLinearOperator.
Merge branch 'feature/coord' into develop
Add prefs for inheritance diagrams.
Refine inheritance diagrams.
Properly raise ShapeError.
Clarify the docstring of sqrt().
Merge branch 'release/coord'
Merge branch 'release/coord' into develop
Merge branch 'master' of github.com:dpo/pykrylov
Merge branch 'master' into develop