Add textmime macro

There is quite a number of functions that need to be defined for a
text mime-type to flawlessly interact with the rest of the system.
If the mime type is not included in Base, this is quite tedious, so
add a macro that defines all the necessary functions appropriately.
Pkg: factor out META_BRANCH (currently "devel").

This paves the way for METADATA versioning via branches. The idea
is that each version of the METADATA format has its own branch.
Incompatible formats can co-exist peacefully because they each have
their own branch in the METADATA repo. Some sort of automated version
of the `remaster.jl` script would be ideal for pack-porting packages
that can be backported to earlier versions. This should be possible
with GitHub service hooks.
fix #4215
Merge pull request #4361 from simonster/methods2

Show method table for foo( + tab at repl
Merge pull request #4425 from ihnorton/rm_pkg1

Remove pkg1
improve inlining of vararg functions (avoid allocating rest tuple)
limit argument type tuple length less aggressively, by trying to determine
  if it is actually growing due to recursion
formatting fixes
remove Int from SmallSigned type union
Merge branch 'master' of github.com:JuliaLang/julia into jb/vararginline
Restrict inv to dense matrices to have a better error for #4439
Get rid of the generic inv implementation as it really is only
applicable for the dense case, which already has its own implementation.
See #4439 also.
Close #4439
try to fix windows compilation problems with method tab-completion
Merge pull request #4404 from JuliaLang/anj/sparse

RFC: Make sparse multiplication work for AbstractArrays
fix #4246. also fix calling convention, although it doesn't matter
Use TOL wherever it is an array, and tol where it is not an array.
Annotate the types for tol and TOL to minimize confusion when revisiting the
code in the future.
Doc: clarify search string vs. char; remove dup. rsearch
fix #4402
addresses issue #4310
WINDOWS: move user preferences to My Documents directory. close #4334