Remove pragmas for non-standard struct packing in the public API

These pragmas specified that structs should be packed in a way
different from the normal way defined by the current platform ABI.
Since these pragmas are in headers part of the public API, and the
pragmas are nonstandard, this is a portability and compatibility
hazard (all code calling the library need to have the same support
for the nonstandard pragma).

Additionally, accessing unaligned struct members (as produced by this
tight struct packing) can give reduced performance or even lead to
crashes on platforms that require strict alignment.

The only theoretical possible benefits of using the pragma are either
matching a certain struct layout defined in some other, fixed ABI
(but since this is an interface defined by this library itself, there's
no such prior binary interface that needs to be matched), or to reduce
the memory usage by packing the structs tighter (where the reduction
would be marginal at best).
Add release builds to Travis and fix warning in release build.
Add nasm to apt-get list for Travis
Remove the executable bit accidentally set on an asm source file
Mark the mktargets shell/python scripts executable
Get rid of trailing whitespace in the platform makefiles
Add the console applications to .gitignore
Remove trailing whitespace in comments

The astyle cleanup keeps trailing whitespace within comments,
but the whitespace here is not significant nor intentional
and thus should be removed.
Rerun astyle on the C++ source files

astyle was only run on .cpp files this time - already in
ff6b66917 where the style cleanup was done initially, not all
.h files seem to have gotten the same styling (rerunning astyle
on .h files at that commit produces a huge diff).
Add a proper include guard to dec_console.h
Remove "pragma once"

The same thing is handled by proper standard C header include guards
in all these files.
Remove commented out pragmas
Merge pull request #102 from mstorsjo/remove-pragma-once

Remove pragma once
Update the readme with current platform support

Both 32 and 64 bit is supported, on windows, linux and OS X,
including x86 assembly code.
rename decoder's intra-prediction prefix from Wels to WelsDecoder.
remove unused intra-prediction functions and declarations
Merge pull request #95 from ethanhugg/travis2

Add release builds (ASM) to Travis
Merge pull request #99 from mstorsjo/gitignore

Add the console applications to .gitignore
Merge pull request #96 from mstorsjo/executablebit

Fix the executable bit on files
Merge pull request #101 from mstorsjo/rerun-astyle

Rerun astyle on the C++ source files