Implementation of deleteat!
Refactor splice!, delete!
Bug fixing only
More symbol exports and C-API example
implement a simple code coverage tool

To use the tool, pass --code-coverage. On exit, for each source file foo.jl for
which we have data, write foo.jl.cov next to the original file, with execution
counts in front of each line, or "-" if no data.

also start consolidating compiler options into a jl_compileropts struct
fix redundant first line count

switch line counters to internal linkage
Travis tests with release and nightly
Replace error() by systemerror() where appropriate

No other semantics should have changed.
More error() -> systemerror()

But this batch needed ios' seek and skip to report whether their failure
has set errno (return -1) or not (-2). I've greped for them in order not
to miss any possible repercussions.
Additional missing systemerror() calls.
Fixes in error-handling of fs.jl.
`flush` return value from Void to Cint
From -one(Coff_t) to -1
Added comments explaining the return -1/-2.
Merge pull request #5439 from aviks/as/travis

Travis tests with release and nightly
Fix #5454
More logical indexing fixes, and add a few more tests
Fix #5453
ctranspose should use conj() for all arrays. fixes #5449
Add inferred macro

inferred(f(x)) calls f(x), checks that typeof(f(x)) matches the
inferred return value, and passes on the return value. See discussion
in #5404

(No at signs in this commit to avoid noise)