Harry: Add support for head

Closes #1367.
Sally: Add support for head

Closes #1368.
Libctl: New formula

Closes #1341.
ds9 7.3.2 (new formula)

Closes #1311.
repeatmasker, repeatmodeler, repeatscout: Add tag

Add tag bioinformatics
plink: Option to skip version webcheck

Closes #1363.
openimageio: make qt optional

qt dependency is optional OpenImageIO needs Qt only for its viewer.

Closes #1361.
delly: update to 0.6.1, avoid bundled bamtools/htslib

Closes #1370.
plink: style nits
openimageio: style nits
nauty: update option
flann: update options
flann: fix octave option
kat 1.0.6

New release (V1.0.6) and updated jellyfish dependency to 1.1.11.

Closes #1346.
New formula: SimpleITK

Closes #1303.
SISL 4.6.0 (new formula)

SISL is a NURBS (Non Uniform Rational B-Splines) software library developed and
maintained by the geometry modelling group at SINTEF ICT, Department of Applied
Mathematics.

Closes #1271.
Numdiff 5.8.1 (new formula)

A program that compares putatively similar files line by line and
field by field, ignoring small numeric differences or/and different
numeric formats.

Closes #1372.
nexusformat: version 4.3.3

Closes #1366.
kat 1.0.6: Add bioinformatics tag
repeatscout 1.0.5: Add optional dependency on trf

To filter your repeat library to remove low-complexity and tandem sequences,
you will neeed to have perl 5.5 (or better; see http://www.perl.com), nseg
(Wooton and Federhen, 1993; see ftp://ftp.ncbi.nih.gov/pub/seg/nseg) and trf
(Benson, 1999; see http://tandem.bu.edu/trf/trf.html).

See http://bix.ucsd.edu/repeatscout/README.txt
See #1338