API and documentation improvements

List of changes:

• Easy user classes transfer from C++ part into UnigineScript via API.
• Serialization support by API.
• Improved constructors of universal variables in API.
• Basic math library in API.
• Calling world script functions from the system script.
• Calling system and world UnigineScript functions via API.
• Application samples:
  • simple engine initialization,
  • functions export from C++ part into UnigineScript,
  • classes export from C++ part into UnigineScript,
  • serialization,
  • integration into Qt application,
  • callbacks.
• Update of GLAppQtWindow.
• engine_config command line parameter.
• Maximal FOV of LightProj is increased to 180 degrees.
• Volume light precision fix.
• No more symbolic links in source packages.
• New SDK installation script.
• Documentation in CHM (compiled HTML) format.
• Updated reference manual.

Unigine reference manual and API documentation now are available in two formats: many HTML files and CHM (compiled HTML). CHM versions provide full-text search and are more convenient in use under Windows: