Added tree build/init/free functions to fmpz_mod_poly and profiling code for
invert, mul, tree.
fix test failure in print/read_pretty
prefer classical multiplication when one polynomial is short
improve algorithm selection for fmpz_poly_gcd
use len2 or n in mullow cutoff
fix t-print_read_pretty some more (var also won't be read if len = 1)
Update padic_exp.

This changes the signature for the underscore function to
operate on fmpz_t's.
Bugfix in padic_log.

The bound on the number of terms used in the logarithm computation
was sometimes to low.  Now I have chosen a bound that I have proven,
see e.g. in my thesis.
Small improvement to padic_log_balanced.

Note that we now reduce y modulo pN on input, and that
this is all the data that we need to take into account
in order to compute the logarithm to precision N.  The
reduction process of (t, r) ensures that only look at
relevant data.
Small fix in fmpz_poly/profile/p-mul_triangle.
Improvements to the padic logarithm function.

Finally sets _padic_log to choose between the rectangular and
the balanced approach (roughly) as suitable.  From looking at
the data on my machine, it seems that something like
(log p) N >= 2^9 is a sensible point to switch algorithms.

Also adds test code for the case when p=2.
Improvements to padic_exp_balanced
fix a subtle bug in fmpz_bit_unpack causing corruption of fmpz_unused_arr
Merge commit 'sebastian/trunk' into trunk
Correctly build NTL interface finally.
Detect errors occurring within foreach loops.
Adds _log_padic_balanced to the header.
Added 32 bit tuning values.
fix definition of _padic_log_balanced
fix a 32-bit warning