audio/libmusicbrainz5: Update to snapshot from 2015-07-06 (e29cc9a)

• The main purpose of this intermediate update is to eliminate unwanted debug information emitted when running console applications.
• Backport commit 36262d6 to eliminate wildcards for dependencies in CMakeLists.txt which CMake complains about (CMP0058). As a result, we can switch to an outsource build.

While here:

• Update LICENSE (LGPL21+) and add LICENSE_FILE
• Remake/rename patches with 'make makepatch'

Changes: https://github.com/metabrainz/libmusicbrainz/compare/release-5.1.0...e29cc9a
PR: 250567
Submitted by: Daniel Engberg <daniel.engberg.lists@pyret.net>