add support for list wise inits

[nathanvan]

On my blog, Harry Hiemstra, writes:

Thanks for making this program available.

I have troubles in getting rstanmulticore working when providing different sets of initial values for the chains. I get the following error message:

Error in combining the results of parallel workers:
The following elements of 'sflist' do not contain samples: 1, 2, 3.

Could you provide an example

The issue seems to be that the list-wise inits are promises that are not evaluated until they reach the workers. I am attempting to modify the code to force evaluation before sending the inits on.

[nathanvan]

Fixed in 0.2.0.