implemented masking to LCFS drawing

Added masking (see core.inPolygon) to core, EFIT, and eqdskreader
modules.  Implemented masking and explicit recalculation of LCFS
on-demand, overwriting RLCFS, ZLCFS values pulled from EFIT data.
Implemented separate method distinguishing between full vector graphic
of machine cross-section (used for plotting routines) and method
returning limiter outline (pulled directly from EFIT data).  In cases
where full vectorization of cross-section is unavailable, method returns
limiter outline.  Note that masking routines still need to be tested.