New experiments with "input_manager", replace literal and builtin_literal with literal_expression and builtin_literal_expression

Additionally:
- Disabled some warnings that occur on boost headers.
- Fixed a mistake that omni-base.props ignored the inherited values for ignored warnings.
Added...
* ... toString and fromString methods for literals (fromString is not yet implemented)
* ... toString for types (implemented only for builtin types)
* ... setValue and getValue to access the current value of a builtin_literal_expression
* ... ValueChanged signal for literals
Upgraded llvm from 3.5 to 3.6 (hopefully fixes travis build)
Upgraded llvm from 3.5 to 3.6 (hopefully fixes travis build)
Merge branch 'master' of https://github.com/daniel-kun/omni
Fixed compile error on g++ regarding default arguments
Fixed compile error on g++ regarding default arguments and linking targets
Merge branch 'master' of https://github.com/daniel-kun/omni
Merge pull request #6 from daniel-kun/coverity_scan

Merge pull request #5 from daniel-kun/master
Merge pull request #8 from daniel-kun/master

Update coverity_scan from master