evalresp: Fix realloc bug.

The return value of realloc is the possibly new pointer to the memory
block. Using the original pointer afterwards could be cause for a crash
if the reallocation caused the pointer to change.
evalresp: Fix "set but unused" warnings.
libtau: Expand tabs for less warnings.
libtau: Remove unused code that causes warnings.
evalresp: Remove unnecessary memset.

This memset is wrong since sizeof(pointer variable) is just the size of
a pointer, not the size of the buffer. Anyway, strncpy is going to
overwrite it.
evalresp: Fix some uninitialized variable.

There are more, but I don't understand the code enough to just blindly
set defaults. I really think this is quite fragile, and assumes all input
is well-formed.
mseed: Fix incorrect return value.

The return type is a pointer, so returning -1 is going to be bad...
libtau: Make precision conversions explicit.

This reduces a significant number of warnings. Many of these variables
are explicitly one type or the other, so I figure making the conversion
explicit will not harm anything.
libtau: Fix unused parameter warning.

I'm a bit surprised that this works, actually. I'm sure a C compiler
would have recognized this trick.
evalresp: Fix warnings about getcwd.

This code is one long filename/path away from a seg fault, though.
evalresp: Fix unused return value warnings.
evalresp: Fix parenthesis warning.

Since bitwise AND is lower precedence than addition, this actually
appears to be wrong. The two bytes would be added and then AND'd with
255, so the result is basically equivalent to one byte.
mseed: Fix signed/unsigned comparison warning.
signal: Remove unused parameters to generalizedBeamforming.
evalresp: Fix signed/unsigned comparison warning.
mseed: Fix strict prototypes.

I noticed these additional warnings on Travis. A C function that takes
no parameters should use (void), not (). The logging functions are
documented as taking const char*, but it's not written that way.
evalresp: Fix strict prototypes.

Also, remove old-style parameter declarations. They're not even ANSI
standard.
Merge branch 'master' into warning-cleanup

Conflicts:
	obspy/signal/src/evalresp/evresp.c
New interpolate() method for Stream and Trace objects.

Currently only wraps scipy.interpolate.interp1d but that already offers
a bunch of options.
Added weighted average slopes interpolation scheme.