Fix 695501: Intelligent cmap remapping.

Use the actual ranges from the cpt-to-gid cmap to optimize the
remapping of ToUnicode cmaps from cpt-to-unicode into gid-to-unicode
format.
Bump version number.
Update change list for 1.6 release.
Avoid redefinition warning from clang when building cmapdump.c

In file included from scripts/cmapdump.c:19:
scripts/../source/fitz/ftoa.c:30:23: warning: redefinition of typedef 'ulong' is a C11 feature [-Wtypedef-redefinition]
typedef unsigned long ulong;
                      ^
scripts/../source/fitz/strtod.c:30:23: note: previous definition is here
typedef unsigned long ulong;
                      ^
1 warning generated.

(Apparently in earlier versions of clang this is an error.)
iOS: Move instance variables from .h to .m

These are private details that, since changes in Xcode, no longer need to
be exposed in the headers.
iOS: Add missing [super viewWillAppear/Disappear] calls

Spotted by xcode6 analyser
iOS: Fix a warning in xcode 6

scrollViewDidEndZooming takes a CGFloat.
iOS: Remove empty didReceiveMemoryWarning implementation
iOS: Fix an analyser warning

In MuDocRef initialise. it spotted cases where self could be released
twice after a failure.
iOS: Enable various warnings to match current best practice
iOS: convert app icons & launch image into image catalogues
iOS: minor cleans ups

unused variables / functions / potential uninitialised variable usage
iOS: tweak types to avoid warnings in 64 bit builds

Still more warnings left.
iOS: Run at native res on iphone6/6+

All that is necessary is to add a launch xib.
iOS: Remove CFBundleIcon* keys from the Info.plist

These are now generated by Xcode at build time from the asset catalogue,
and the CFBundleIconFiles we had here was upsetting the app store validator.
Fix warnings.
fix memory leaks in load_sample_func and pdf_load_compressed_inline_image

In load_sample_func, the stream is not closed and thus leaked if one of
the fz_read_byte or fz_read_bits calls throws (which might happen e.g.
on a Deflate data error).

In pdf_load_compressed_inline_image, the allocated buffer is not freed
if one of the stream initializers or the tile creation throws
(fz_open_leecher does not take ownership of the stream).
more liberally accept page trees with unexpected content

pdf_lookup_page_loc_imp currently throws if any object in the page tree
is neither a /Pages node nor a /Page leaf. This unnecessarily rejects
slightly broken documents such as the ones from
https://code.google.com/p/sumatrapdf/issues/detail?id=2582 and
https://code.google.com/p/sumatrapdf/issues/detail?id=2608 .

pdf_count_pages_before_kid currently wrongly throws if a /Pages node
doesn't contain any kids and correctly states so (which even seems to
be permitted by the PDF specification).