Standardize bounds in _linprog_util
Standardize bounds in _linprog_util

Convert various ways to specify bounds to a standardized 2-D np.array of float in _clean_inputs().
Simplify _presolve(), _get_Abc(), _postsolve(), _check_results(), _postprocess().
Change doc strings.

e-q/scipy,perimosocordiae/scipy,matthew-brett/scipy,WarrenWeckesser/scipy,Eric89GXL/scipy,tylerjereddy/scipy,e-q/scipy,ilayn/scipy,tylerjereddy/scipy,scipy/scipy,rgommers/scipy,rgommers/scipy,tylerjereddy/scipy,scipy/scipy,Eric89GXL/scipy,Stefan-Endres/scipy,Stefan-Endres/scipy,scipy/scipy,andyfaff/scipy,perimosocordiae/scipy,andyfaff/scipy,vigna/scipy,andyfaff/scipy,mdhaber/scipy,grlee77/scipy,rgommers/scipy,vigna/scipy,Eric89GXL/scipy,zerothi/scipy,vigna/scipy,Stefan-Endres/scipy,zerothi/scipy,e-q/scipy,Eric89GXL/scipy,ilayn/scipy,Eric89GXL/scipy,scipy/scipy,ilayn/scipy,WarrenWeckesser/scipy,matthew-brett/scipy,anntzer/scipy,matthew-brett/scipy,tylerjereddy/scipy,rgommers/scipy,perimosocordiae/scipy,anntzer/scipy,scipy/scipy,nmayorov/scipy,anntzer/scipy,e-q/scipy,perimosocordiae/scipy,mdhaber/scipy,e-q/scipy,endolith/scipy,Stefan-Endres/scipy,endolith/scipy,matthew-brett/scipy,vigna/scipy,zerothi/scipy,endolith/scipy,endolith/scipy,andyfaff/scipy,ilayn/scipy,nmayorov/scipy,zerothi/scipy,endolith/scipy,grlee77/scipy,perimosocordiae/scipy,zerothi/scipy,nmayorov/scipy,anntzer/scipy,Eric89GXL/scipy,mdhaber/scipy,anntzer/scipy,tylerjereddy/scipy,rgommers/scipy,perimosocordiae/scipy,andyfaff/scipy,mdhaber/scipy,nmayorov/scipy,andyfaff/scipy,scipy/scipy,endolith/scipy,grlee77/scipy,mdhaber/scipy,grlee77/scipy,Stefan-Endres/scipy,anntzer/scipy,WarrenWeckesser/scipy,WarrenWeckesser/scipy,ilayn/scipy,matthew-brett/scipy,zerothi/scipy,Stefan-Endres/scipy,mdhaber/scipy,grlee77/scipy,vigna/scipy,WarrenWeckesser/scipy,nmayorov/scipy,ilayn/scipy,WarrenWeckesser/scipy