Changed cmake python library search startegy for crosscompiling
Fixing documentation links
disabling java bindings for xfeatures2d module due to build errors
Fixed java tests build

- disabled xfeature2d dependency for java wrappers
- fixed java wrappers build after cmake rerun
- disabled opencv_ml tests temporarily
- fixed Imgproc usage in java tests
Fixed android java test build
Fixed android samples build
typo: rect -> roi
Merge pull request #3199 from apavlenko:fix_docs_typo
Merge pull request #3196 from PhilLab:patch-4
Merge pull request #3189 from mshabunin:python_cross_build
Fixed some failing java tests

- fixed lena.png extension
- fixed getTextSize wrapper
- added junit html report generation
Merge pull request #3198 from mshabunin:java_test_fix