This commit adds a `PC_Transform` function that returns a new patch with its data transformed based on the passed `pcid`.
In contrast to `PC_SetPCId` this function may reinterpret the data if dimension interpretations, scales or offsets are different in the new schema. In the future `PC_Transform` will also re-project the patch data if the schema `srid` has changed, but that is not yet supported.
This commit adds a PC_Range function. This function returns a patch of "count" points. These points are selected from the start-th point in the input patch.
* PC_Sort and PC_IsSorted
* fixing -Wdeclaration-after-statement warnings
* using sort_r for a portable definition of qsort_r/qsort_s
* uncompression fallback for lazperf/is_sorted
* NEWS updated, sort_r github reference and README added
