sync develop with master + bump version to 3.4.0.dev0

add SHA256 checksum to cadaver easyconfig

{tools}[dummy/dummy] EasyBuild v3.3.1

release EasyBuild v3.3.1

{tools}[intel/2017a] cadaver v0.23.3

{lang}[GCCcore/6.4.0] byacc v20170709

bump version to 3.3.1 and update release notes

{lib}[GCCcore/6.4.0] libsodium v1.0.12

{lib}[GCCcore/6.4.0] libspatialindex v1.8.5

{tools}[GCCcore/6.4.0] expat v2.2.1

{lib}[GCCcore/6.4.0] LibUUID v1.0.3

{lib}[GCCcore/6.4.0] libpng v1.6.30

{bio}[foss/2016b] VERSE v0.1.5

added easyconfig for miniconda

prepare release notes for eb331

cleanups for easyconfigs related to GCC 6.4.0