make import/using .Foo do a relative search for Foo, and the old syntax search from Main (the top level).
addresses #2375

this is quite disruptive, but I think I prefer it. after all, most of
the imports in Base are of internal modules, so they should be marked as
such.
fix inverse trig degree functions
Remove image.jl from extras/
Merge pull request #2765 from simonbyrne/master

Fix inverse trig degree-valued functions
fix #2766
fix the inconsistency described in #2763
this was a leftover from an older AST representation
Updates docs for publishing packages

Instructions to ensure that METADATA is up-to-date before registering a
new package.
Merge pull request #2769 from jiahao/doc-pkg-upd

Updates docs for publishing packages
Merge pull request #2767 from staticfloat/travis

Travis updates
Set: implement using a Dict{K,Nothing} instead of Dict{K,Bool}.

This is Jeff's brilliant idea: since we store Array{Nothing} using
zero space because there's only one possible Nothing value, this is
a way to use the Dict implementation for sets without wasting space
storing the array of values.
fix #2775, restore long versions of command line opts
Merge branch 'master' of github.com:JuliaLang/julia into jb/relativeimport
make relative imports explicit based on the number of leading dots
fix mistake in git example commands
Redirect patchelf scan's stderr to /dev/null, closes #2776
Merge pull request #2777 from staticfloat/patchelfoutput

Redirect patchelf scan's stderr to /dev/null, closes #2776
fix #2780
Merge branch 'master' of github.com:JuliaLang/julia
Introduce USE_SYSTEM_RMATH to allow for system-packaged Rmath
Add in Rmath to travis config