improve the build system

[mweastwood]

We now have the following behavior

On OSX (tested on Travis CI)

• install science/cfitsio and science/healpix using Homebrew.jl
• if pkg-config --version fails, pkg-config is installed using Homebrew.jl
• deps/src/wrapper is compiled from source

On Xenial (tested locally)

• libcfitsio3-dev, libchealpix-dev, libhealpix_cxx-dev installed using apt
• deps/src/wrapper is compiled from source

On Trusty (tested on Travis CI)

• libcfitsio3-dev installed using apt
• libchealpix and libhealpix_cxx are built from source
• deps/src/wrapper is compiled from source

Other Linux (tested on tkelman/c6g6 while pre-compiling dependencies for the next case)

• Everything built from source

Linux with libtool missing (tested with local PackageEvaluator.jl run)

• pre-compiled libraries are downloaded from https://bintray.com/mweastwood/LibHealpix.jl/dependencies (these libraries are built using the tkelman/c6g6 Docker image to try to make sure they work on as many linux distributions as possible)

Closes #20 Closes #27 Closes #29 Obviates the need for JuliaCI/PackageEvaluator.jl#169

@tkelman I would really appreciate it if you could give this a quick review. Most of this PR was trial and error, and I generally have no idea what I'm doing here.

[codecov[bot]]

Codecov Report

Merging #30 into master will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #30   +/-   ##
=======================================
  Coverage   96.41%   96.41%           
=======================================
  Files           7        7           
  Lines         279      279           
=======================================
  Hits          269      269           
  Misses         10       10

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 7406dba...4610013. Read the comment docs.

[codecov[bot]]

Codecov Report

Merging #30 into master will not change coverage. The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #30   +/-   ##
=======================================
  Coverage   96.41%   96.41%           
=======================================
  Files           7        7           
  Lines         279      279           
=======================================
  Hits          269      269           
  Misses         10       10

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 7406dba...7eaa036. Read the comment docs.