Bug with tuple-specified linestyles

[MBravoS]

base_funcs.dict_splicer() breaks when it receives a tuple specifying the linestyle of a plot. We should add a test for data type when linestyle is given as a key in plot_par, and ensure that it gets passed correctly (wrapping it in a list works fine).

[AstroRobin]

This also has further-reaching implications for any color being given as a tuple (e.g. (r,g,b,a)).
To fix this, we can check the first element of any tuple given to dict_splicer() if it is purely a 'string' OR the first element is explicitly numeric, then it should be treated as a single value rather than a set of values for multiple lines.

[MBravoS]

Solve as of version 0.4.1.2.