* bindings: Remove relative header paths
Use the include paths set on the command line the way
they're supposed to be used.
* Also remove some redundant include paths
* Fix SWIG include dirs
- Switch to AUTOMOC for Qt classes
- Eliminate globbing of source subdirs
- Call `include_directories()` in top-level CMakeLists
- Make header files PUBLIC library sources
- Make other sources PRIVATE
The resetting of `CMAKE_SWIG_FLAGS` to the empty string in the bindings'
CMakeLists.txt files was clearing away the definitions for things like
`USE_IMAGEMAGICK` and `USE_BLACKMAGIC`, causing the bindings to be built
_without_ those classes even if they're available in the library.
* Remove a SWIG pragma from Frame.h (gcc warns on it)
* Place the equivalent %warnfilter in the openshot.i files
* Set openshot.i PROPERTY GENERATED_COMPILE_OPTIONS with flags to
disable warning spew in generated SWIG code, if -Wall is used
(Also, remove 'using namespace std' from Frame.h, and add std::
prefixes to necessary variables.)
