Support for mips/mipsel

Fix for issue #98

Avoid unaligned memory access on architectures that don't support it.
Fixed endianness related issues. 
On Sat, Oct 04, 2014 at 10:51:14AM -0700, domibel wrote:
> @jkbonfield , Could you please update the https://github.com/jkbonfield/htslib/tree/SPARC branch?
> The status right now is: This branch is 8 commits ahead, 96 commits behind samtools:develop

I'm wary of rebasing it as it's been in a public repository already
and I haven't been able to verify it actually works in the newer form
(I don't have the SPARC any more).

So I did a merge and conflict fix.  It was a total mess as *some* of
the original pull request has been merged in with the main develop
branch, but not all (and some got rewritten). Also since then there
has been mass tab vs space changing to add more fun into the mix.

My patch is primarily therefore simply the addition of ua_read/write
macros for supporting unaligned memory access.  It's probably better
off to just diff against develop and recode the changes so it's safe
from N-way merging cruft and clean, however I don't have any local
hardware to test on.

James

-- 
James Bonfield (jkb@sanger.ac.uk) | Hora aderat briligi. Nunc et Slythia Tova
                                  | Plurima gyrabant gymbolitare vabo;
  A Staden Package developer:     | Et Borogovorum mimzebant undique formae,
https://sf.net/projects/staden/   | Momiferique omnes exgrabure Rathi. 


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