OpenNI: Modify samples' directory

Closes #607.
Armadillo: Remove boost dep and add arpack.

Closes #619.
idcoefs 2.1.1: New Formula

Compute the condensed identity coefficients for pairs of individuals.

Closes #610.
Update to PETSc 3.4.

- Download petsc-lite for smaller tarball
- Build with shared libs
- Compatible with petsc4py 3.4 and SLEPc 3.4.

Closes #343.
New formula for TAO.

TAO is a toolkit for optimization that builds upon PETSc.

Closes #335.
New formula for SLEPc.

Closes #334.
minia 1.6088
dsk 1.6066: New formula

DSK is a k-mer counting software, similar to Jellyfish. Jellyfish is
very fast but limited to large-memory servers and k ≤ 32. In contrast,
DSK supports large values of k, and runs with (almost-)arbitrarily low
memory usage and reasonably low temporary disk usage. DSK can count
k-mers of large Illumina datasets on laptops and desktop computers.
spades 3.0
sga 0.10.13

No longer fails to build with clang.
sailfish 0.6.2: New formula

Sailfish: Alignment-free Isoform Quantification from RNA-seq Reads
using Lightweight Algorithms
http://arxiv.org/abs/1308.3700
insighttoolkit: cleanup python usage.
lp_solve: cleanup python usage.
opencv: cleanup python usage.
qgis: cleanup python usage.
shogun: cleanup python usage.
vtk: cleanup python usage.
bedtools 2.18.2

Closes #611
Merge commit 'a4b94013890ed54bad7ed901c1faa890fcf970fe'