Add jpeg recipe with custom CMake file.

[jakirkham]

Closes #355

Simply takes ( #355 ) and squashes it into one commit. Also added executable permissions to the build scripts (bld.bat and build.sh), which doesn't really matter, but is nice.

cc @gillins @patricksnape @msarahan @ocefpaf

[jakirkham]

Once CI passes, would you like to do the honors, @ocefpaf?

[ocefpaf]

Thanks @jakirkham!

[jakirkham]

Thanks for keeping an eye on this and getting it in, @ocefpaf. We should rebuild hdf4 once this is released to see how it goes.

[ocefpaf]

We should rebuild hdf4 once this is released to see how it goes.

I am on it.

[dopplershift]

Rebuild jasper as well, since it's linked against jpeg8 (conda-forge/jasper-feedstock#2). Otherwise, installing conda-forge's jasper package out of the box is broken now.

[ocefpaf]

See conda-forge/jasper-feedstock#3

[dopplershift]

I wish there were some way not to pin the package to a particular version of jpeg, but to note that it needs the version it built against.

[msarahan]

@dopplershift I think that's similar to the ideas in conda/conda-build#848 and other related PRs - you should weigh in there with your request and any ideas for implementation.