cleaned up GP interfaces and added an own file for them
added new files
Merge pull request #1303 from karlnapf/develop

moved GP modular inferfaces to its own file
added GaussianProcess in modular interface structure
Merge pull request #1304 from karlnapf/develop

added GaussianProcess in modular interface structure
changed include order to get rid of some error in modular
Merge pull request #1305 from karlnapf/develop

changed include order to get rid of some error in modular
Minor changes to build scripts: Bogus whitespaces, missing debug output, missing make dependecies