sync develop with master + bump to v3.5.1dev

{tools}[dummy/dummy] EasyBuild v3.5.0

release EasyBuild v3.5.0

bump version to v3.5.0 & update release notes

avoid auto-downloading of parcel in gdc-client 1.3.0 easyconfig

{lib}[intel/2017b] FoX v4.1.2

{lib}[intel/2017b] gdc-client v1.3.0

{bio,lib}[GCCcore/6.4.0,intel/2017b] BLAST+ v2.7.1, LMDB v0.9.21

{vis}[foss/2017b] ImageMagick v7.0.7-14, Ghostscript v9.22, LittleCMS v2.9

fix order of extensions for FSLeyes, add missing MarkupSafe (dep for Jinja2)

adding easyconfigs: ImageMagick-7.0.7-14-foss-2017b.eb, Ghostscript-9.22-foss-2017b.eb, LittleCMS-2.9-foss-2017b.eb

{chem,math}[foss/2017b] Cantera v2.3.0, SUNDIALS v2.7.0 + deps

{data,devel,math}[foss/2017b] GDAL v2.2.3, GEOS v3.6.2, SWIG v3.0.12

{geo}[foss/2017b] SpiceyPy v2.1.0

fix checksum for Szip 2.1.1

{devel}[foss/2017b] SCons v3.0.1 with Python 3.6.3

add Log4perl extension to Perl 5.26.0 easyconfigs (+ clean up checksums)

adding easyconfigs: GDAL-2.2.3-foss-2017b-Python-3.6.3.eb, GEOS-3.6.2-foss-2017b-Python-3.6.3.eb, SWIG-3.0.12-foss-2017b-Python-3.6.3.eb