readdlm has_header is now header, skipstart added

fixes #6869
- `header` takes a boolean value and behaves like `has_header` or DataFrames `header` option.
- `skipstart` takes a positive integer value and behaves like DataFrames `skipstart` option.
Improvements to regex performance.
Remove trailing whitespace
Make partitions more robust

Implement partitions(n, m) in the cases where n = 1 and m > n,
as well as the analogous situation for partitions(v::Vector, m).
Remove unnecessary check
Improved dict printing

This is an attempt at improving the situation for issue #1759.  I've added
slightly enhanced `summary`s with information about the number of k/v pairs for
Associative and Key/ValueIterator types.

This PR keeps the old behavior (mostly) as `showcompact`. I then added new
functionality in `show` and `showlimited` for Associative and
Key/ValueIterators, printing newlines as delimiters between key/value pairs.
When output is limited, keys are truncated to the left third of the TTY screen
and values are truncated at newlines or the screen edge, with the `=>`
separators aligned.
Boundschecks for searchsorted & remove step(r::Range)==0 tests

1) Check bounds on the more low-level searchsorted* methods.  Before
an error like this was possible:
```
julia> searchsortedfirst([1:10], 5,  -10, 7, Base.Order.Forward)
zsh: segmentation fault (core dumped)
```

2) Removes the step(r)==0 tests as ranges cannot have 0 steps (I
   think)

Note that the low-level sort! methods also do not check bounds.
Probably this should also be rectified.
Fix for LLVM trunk changes that broke enableUnsafeAlgebraIfReduction.
faster Float32 to Int64 itrunc

adds a type argument fptosi(T, x). most other similar intrinsics
already have this argument.

support more types in eqfsi and eqfui. however all-64-bit is faster
than using mixed sizes, so this is mostly cosmetic, but makes the
intrinsics easier to use.

helps #7076 if itrunc is used
Merge branch 'master' of github.com:JuliaLang/julia
Merge pull request #5706 from mbauman/showdict

RFC: Moderately improved dict printing
Merge pull request #7072 from wsliang/partition

Implement corner cases for partitions
generalize indexin definition
use static_show for errors during finalization
use correct uvfinalize method for PipeServer. fixes #7020

remove double shutdown check in jl_close_uv; fixed upstream.
Merge branch 'master' of github.com:JuliaLang/julia
Merge pull request #7086 from Jutho/jh/indexinfix

generalize indexin definition
add static codegen for jl_is_leaf_type and jl_subtype
Merge pull request #7059 from tanmaykm/readcsv

readdlm has_header is now header, skipstart added
Merge pull request #7078 from mauro3/sort_bounds_check

WIP: Boundschecks for searchsorted & remove step(r::Range)==0 tests