Minor updates to EGLplus Config

- Added 3 new attribute getters.
Merge branch 'develop' into feature-boost-python
Merge branch 'feature-boost-python' of github.com:matus-chochlik/oglplus into feature-boost-python
Added value type to OALplus device specifier range
Merge branch 'develop' into feature-boost-python
Multiple changes in OALplus

- Added string queries to Context.
- Added an example showing the usage of string queries.
Merge branch 'develop' into feature-boost-python
Multiple changes in OALplus

- Fixed a type in the documentation.
- Removed a const qualifier on the Source::MaxDistance setter.
Merge branch 'develop' into feature-boost-python
Minor update in OALplus

- Removed const qualifier from the Source::Gain setter.
Merge branch 'develop' into feature-boost-python
Updated the Python bindings

- Updated bindings for EGLplus
  - Configs
- Added the first bindings for OALplus
  - enumerations
  - String and StrLit
  - Device
  - Context
  - Buffer
  - Source