remove EMachineType and related functions

[vigsterkr]

https://github.com/shogun-toolbox/shogun/blob/develop/src/shogun/machine/Machine.h#L32

this enum needs to go because this will not be used (or usable when the plugin framework is in place).

[mrkarna]

Hi Viktor, Should I take up this task of removing all enum data types with their integer value? Thanks

[vigsterkr]

@mrkarna try to give it a go and send in a pr

[mrkarna]

@vigsterkr Do I need to remove only EMachineType or all the three enums (EMachineType, ESolverType and EProblemType). Thanks