#887 Recorder changes output format for complex numbers

[Jason Fuller]

The recorder will sometimes change format for complex numbers, particularly 'i' vs. 'j' after the first time step. This may indicate that it grabs the initial value in the objects format, then switches to the recorder's imposed format at a later period. This may be minor, but may by indicative of further issues.

See: https://sourceforge.net/p/gridlab-d/discussion/842562/thread/84c18d4b/?limit=25

[David P. Chassin]

There needs to be an output format property spec instead of a global complex format spec.