Added plantuml extension

Aligned strings in CMakeList

Modified the check on plantuml extension

Some fixes

Moved find_host_program for plantuml script
fix thin-prism coefficients at 0's in the stereo calibration function unless the flag CALIB_THIN_PRISM_MODEL is explicitly set
Merge pull request #1330 from lenlen:plantuml
functions getDefaultClassifierNM1() and getDefaultClassifierNM2() allow to implicitly load the default classifiers when creating a ERFilter object
Merge pull request #1445 from vpisarev:stereocalib_quick_fix
renamed getDefaultClassifierNM{1,2}() to loadClassifierNM{1,2}() and added "const std::string& filename" parameter (mandatory).
first parameter of createERFilterNM1/createERFilterNM2 is now mandatory. changed the sample program to use the new prototypes
The thin prism distortion coefficient related small bug is fixed.
Merge pull request #1446 from lluisgomez:scene_text_detection_NM_fix2
Merge pull request #1458 from look4pritam:my-branch