Changes to haskell interface requested by Greg
update haskell tree generation script
Merge tag '1.8.1' into develop

Official release tag 1.8.1
automatic code generation
Squash-merged in issue_554 branch, #554
Added fix to 94902445f7b51d6a6ebff481385be288cf03d208
Fixed bug in linspace, #554
Renamed SX --> SXElement, #982
Fix to 29d74b8f18894dfbd837d58c95d8daa613487b37
Fix (2) to 29d74b8f18894dfbd837d58c95d8daa613487b37
Renamed SXMatrix --> SX, #982
Removed all occurrences of SXElement in examples, #982
Fixed displaying of SX, DMatrix, #982
Introducing a new CasADi interface to Snopt

-- with much love from Greg
Added SXElement::sym (replaces SXElement(string)) #983
Removed current SXElement(string) usage, #983
Updated GenericMatrix::sym overloads #983
Merge branch 'develop' of github.com:casadi/casadi into develop
Replaced ssym with SX::sym in the symbolic core, #983
Replaced msym with MX::sym in the symbolic core, #983