#24 Added exception wrapping constructor to all exceptions.
#24 Use wrapper constructor if possible.
Update error messages in frontend.
Merge branch 'master' into WrapperExceptions
Merge branch 'master' into WrapperExceptions
Merge branch 'master' into WrapperExceptions
Merge pull request #238 from HPI-Information-Systems/WrapperExceptions

Wrapper exceptions
Merge branch 'master' into Algorithm_DBSystem

Conflicts:
	frontend/src/main/java/de/metanome/frontend/client/input_fields/DatabaseConnectionInput.java