Remove unused basegfx::copySign

Change-Id: I8e5e429b0f0b0cfa2dc65b8e57649bfa722b40e0
Remove unused basegfx::tools::containsOnlyHorizontalAndVerticalEdges

Change-Id: I8a8b7a5b47cd9e566c1b3154a527c78a8fcbd7df
Remove unused basegfx::unotools::homMatrixFromMatrix

Change-Id: I92afab7cfae885dce76b9ffff0d98b8b9a39d85f
Remove unused basegfx::tools::equal

Change-Id: I2fb3121c711dfdd1e2081681864a6f4753960a81