download/compile xz for building/decompressing tarball in OS X installer

On OS X, we previously packed a locally installed xz into the installation
package and unpacked it during installation, if xz is not available on the
target machine. This can lead to problems if xz was installed by a package
manager like Homebrew, as symlinks would get packed instead of the real
binary.

We now download and compile xz statically on the fly, which removes the
need for xz on both the developer and the deployment machine.
document that encrypted home directories are not supported

According to the Debian/Ubuntu bug, there is a workaround but
it is not always safe to use, hence document that it is not supported.
Closes #1793
fix error for the "posix-local" target in build script

This fixes #1800 in a slightly different manner.
document that the home directory should be in /home for linux builds

Otherwise, it does not get automatically mounted in the schroot.
Recommend using a VM in case of such a scenario. Closes #1804.
perform release builds in the specified order
release 0.12.1
bump up VERSION to 0.12.2-dev
correct changelog for 0.12.1
wkhtmltoimage: set stdout to binary mode before writing to it on Windows

This fixes #1758 and is essentially porting the fix for issue 61 on
Google Code (48bc4c82eb4b0fc4e78b865a15d957ce59280990).
fix [sitepage] and [sitepages] not working without HTML headers/footers

This fixes #1808 and is an update to ebf825cd6b91a11675bbaa570d9d418af900cca2,
which did not handle it for the --{header,footer}-{left,center,right} options.
added variable 'isodate' for substitution in headers/footers

This is in addition to the locale-dependent 'date' variable, as
the server system locale where wkhtmltopdf is launched is not always
a good default choice. Closes #1772
do not allow overriding the header/footer settings for cover pages

This was discovered in #1676, where using a command-line like:

  wkhtmltopdf cover cover.html --header-html header.html page.html output.pdf

would override the settings for the cover page and not apply the
--header-html for the URL page.html. This may be unexpected behavior
for most users, but the manual clearly states that the options FOLLOW
the URL/file name, as in:

  cover <input url/file name> [PAGE OPTION]...
  (page)? <input url/file name> [PAGE OPTION]...

So, in the above example it actually means the following

  URL1: cover cover.html --header-html header.html
  URL2: page.html
  OUT:  output.pdf

To fix this, we parse the other page options for a cover page and
then set the header/footer settings to blank values to ensure that
they are not shown on a cover page.
set page margins correctly via header/footer heights for multiple URLs

In 80cbcc5db95eb48127a2d1418653e8643ad74f46, the ability for
auto-calculation of the header/footer height was implemented.
However, in case of multiple page objects (i.e. URLs) being present
for conversion, the calculated height for only the FIRST page object
was used -- the heights for the second and further page objects were
being ignored. In case a cover page was specified first (which has
no header/footer by design) without an explicit margin, then the
top/bottom margins would be set to zero -- which would hide the
header/footer content.

The solution is to use the maximum value across all the page objects,
so that there is enough space for the header content across all page
objects. Fixes #1676
Typo fixes for might and too.
Fix the directory to execute tar in build_posix_local
update OpenSSL to 1.0.1i and libpng to 1.5.19
minor tweak to enable installation on 32Bit OS X (10.6.x, 10.7.x)
Fix cut-n-paste looking error where the header spacing is assigned to the footer spacing
update OpenSSL to 1.0.1j
fix build failure with unpatched Qt >= 5.3

This was originally reported as https://bugs.debian.org/763216