Typo breaks debug build for Android platform.

- enable auto-wrap of VideoCapture;
- minor refactoring of generated code templates.

Also, removed the one from modules/python/src2/cv.py and cleared its
executable bit, since it's not a script.

Common part of all source files is extracted to special header

Based on pull request #31 (thanks to Eric Christiansen)
Support for Java is turned off by default and can be enabled setting
BUILD_opencv_java to ON (e.g. cmake -DBUILD_opencv_java=ON ..)