Implementation of deleteat!
Refactor splice!, delete!
Bug fixing only
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.
Added DataType to the list of highlighted type words in julia-mode.el.
add bounds errors for range indexing of UTF8String. fixes #5446
Merge pull request #5447 from patrickeganfoley/master

Added DataType to the list of highlighted type words in julia-mode.el.
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