(CModel::prependValidator(), CModel::appendValidator()) (Enh #2259 rework)
Tests, code style fixes and changelog gramar corrections
Merge pull request #2607 from creocoder/cmodel-improve

(CModel::prependValidator(), CModel::appendValidator()) (Enh #2259 rework)
CUrlValidator +  didn't respect custom  value.
Fixes #2529: Silenced all chmod calls to prevent "chmod() operation not allowed" error on NTFS
fixed tests