media-gfx/enblend: Bump version to 4.2.0_p20161007

media-gfx/enblend: Bump version to 4.2.0_p20161007

Gentoo-bug: 577512, 593094, 595630

The 4.2.0 release has missing CMake files, thus doesn't build, and
there are general runtime bugs. This patch is from upstream that
fixes all these issues.

* Added more depends for document building
* Added fix for document fonts access violation
* Changed to EAPI 6
* Added SIMD use flag
* General ebuild tidy ups
* Depend on Boost version >=1.62 (due to C++11/14)

Signed off by: Jonathan Scruggs (j.scruggs@gmail.com, irc: Dracwyrm)
Closes: https://github.com/gentoo/gentoo/pull/2510

Signed-off-by: David Seifert <soap@gentoo.org>