Merge pull request #1192 from lambday/feature/log_determinant

EigenSolver added, implementation using Eigen3 added
linspace unit test
Merge pull request #1193 from iglesias/develop

linspace unit test
move risk() from StructuredModel to DualLibQPSOSVM
Merge pull request #1185 from hushell/develop

move risk() from StructuredModel to StructuredOutputMachine
Update gitignore with files created by unit tests
json files and combined_kernel.weights
Fix typo in file extension: from hfd5 to hdf5
Merge pull request #1194 from iglesias/develop

Update gitignore and typo fix
Basic classes
Merge pull request #1186 from van51/feature/hashing

Hashing N-gram / String Converter and tokenizer
Rational approximation base added (log-det)