Added test for pipe_proc.tp logic.  Original change now fails these
tests without the added logic.
Added an option to ignore differences between the min, max, display min
and display max values in the headers for tests, then use this option
for the tp tests.
Fixed a bug in pipe_proc.ext where the function would change the size of
the y data if the x data had been fourier transformed.
Added a few tests to check the fix.
Merge branch 'master' into pipe_tp_fix
Merge remote branch 'upstream/master' into pipe_tp_fix
Merge pull request #16 from tjragan/pipe_fix

BUG: Two NMRPipe related fixes.
STY: PEP8 on multiple files