Merge 2.4 into master

Original pull requests:

* #1163 from kdrobnyh:Morphology
* #1187 from kdrobnyh:mean_and_sum
* #1189 from pengx17:2.4_sort_by_key
* #1216 from alekcac:sphinx
* #1231 from SpecLad:static-ts
* #1232 from StevenPuttemans:fix_wrong_documentation
* #1233 from vpisarev:24_ipp_78
* #1235 from WonderRico:bugfix_dshow
* #1237 from SpecLad:xls-separate-wh
* #1239 from Daniil-Osokin:fix_build_of_camera_calibration_android_sample
* #1242 from asmorkalov:android_native_cam
* #1244 from vkocheganov:bugfix_3179
* #1246 from StevenPuttemans:bugfix_3206