New release GPstuff v3.4

[Aki Vehtari]

GPstuff 3.4

Improved functions since 3.3
- GP_IA improved autoscale and display options
- GP_KFCV optional return values for cvpreds (f,lp,y)
- GP_LOOEG approximate gradients for EP-LOO (no implicit terms)
- GP_OPTIM new options 'lambda' and 'lambdalimit' used by fminscg
- GP_SET new option 'savememory' for memory saving in gradient calculations
- FMINSCG new options 'lambda' and 'lambdalimit'

Other changes
- SuiteSparse v 3.4 included in the distribution package
- easier installation of compact support support
- gp/demos renamed to gp/demodata
- Few bug fixes and several documentation fixes

Updated documentation
- http://arxiv.org/pdf/1206.5754
- new developer documentation in appendix E
- typo fixes
- in addition of using optimset, it is possible to construct an option
structure manually