STY: npymath: tabs -> spaces, long lines
ENH: Check for, and use all C99 complex functions if available

Previously, a number of functions operating on complex numbers from C99
were checked for during the configuration stage.  If they existed, they
were used.  This commit extends this to all of the C99 complex
functions.

All of our local implementations are now in npymath, instead of being
spread between npymath and umath/funcs.inc.src. Functions that numpy has
but C99 does not are still in funcs.inc.src.