create generic worker pool wrapper

[plastikfan]

The boost wrapper will wrap the underlying ants worker pool and expose functionality that matches the legacy worker pool.

[plastikfan]

Just some notes about the design of the ants worker pool that should be acknowledged:

• the go routine associated with each worker, has a lifetime that exists only for the current job
• workers are stored in a sync.Pool
• each work has its own job queue
• workers are created on demand
• there are 2 types of pool, withFunc and without Func
• with func: CTOR: NewPoolWithFunc, UNIT-OF-WORK: func(i ants.InputParam)
• without func: CTOR: NewPool, UNIT-OF-WORK: func()
• when working with waitgroups and posting new jobs, there has to be a waitgroup.Add for each posted job, because the go routine's lifetime spans only the timespan of the job (the wrapper will take care of the Add)

[plastikfan]

In the wrapper, to make the pool easier to work with, we could various different UNIT-OF-WORK interfaces:

• simple/ants-native: func()
• simpleE: func() error
• withInput: func[I](input I)
• withInputE: func[I](input I) error
• withOutput: func[O]() O
• withOutputE: func[O]() O, error
• withManifold: func[I, O](input I) O
• withManifoldE: func[O](input I) O, error

[plastikfan]

ants contains a proprietry Logger interface. This needs to be replaced by the standard structured logger.