Log message

Massive hypergeometric patch

* Implemented asymptotic expansions for 0F1 and 1F1
* Implemented 2F0 and hypergeometric U
* Implemented hypercomb() for evaluation of composite hypergeometric expressions
* Fixed erf, erfi, erfc, airyai, airybi to use asymptotic hypergeometric
expansions for all real or complex arguments (TODO: the same for Bessel
functions, etc)
* Deprecated the poor low-level complex series for erf and erfc
* Implemented a helper function mag(z) that gives a quick magnitude estimate of
a number
* Some other small changes

	Modify	/trunk/mpmath/__init__.py	diff
	Modify	/trunk/mpmath/function_docs.py	diff
	Modify	/trunk/mpmath/functions.py	diff
	Modify	/trunk/mpmath/libhyper.py	diff
	Modify	/trunk/mpmath/mptypes.py	diff
	Modify	/trunk/mpmath/tests/test_functions2.py	diff